A synopsis of Asclepias (Apocynaceae: Asclepiadoideae) in tropical Africa

Summary

In preparation for two major regional Flora accounts, Asclepias has been reassessed in tropical Africa. 38 species not assigned to the allied genera Aspidoglossum, Glossostelma, Gomphocarpus, Margaretta, Pachycarpus, Stathmostelma, Stenostelma or Xysmalobium are recognised in the region. Nine species and one subspecies are described for the first time. The inclusion of Trachycalymma again within Asclepias requires four new combinations. A further three new names or combinations are required for the transfer of Odontostelma welwitschii, Schizoglossum alpestre and Stathmostelma verdickii to Asclepias. Five names are lectotypified, and a neotype proposed for Gomphocarpus meliodorus. The conservation status of all species is assessed.

Introduction and Historical Treatment

Satisfactory delimitation of genera in the Asclepias L. complex has been problematic since at least the time of N. E. Brown, whose introduction to Xysmalobium R. Br. in the Flora of Tropical Africa (Brown 1902: 299) included the following note: “Undoubtedly Xysmalobium, Asclepias and Schizoglossum E. Mey. are but artificial divisions of one natural genus, since they cannot be separated by characters that do not break down at some point”. Nevertheless, Brown went on to assign species to the three genera on the basis of the form of the corona — cucullate in Asclepias, dorsally flattened in Schizoglossum, and thickened or laterally compressed in Xysmalobium. Other genera such as Margaretta Oliv. and Pachycarpus E. Mey. were recognised on the basis of other coronal peculiarities — the petaloid corona of Margaretta, and coronas with a strongly keeled basal portion and a long inflexed tip in Pachycarpus. The corona offers useful characters for species delimitation, but appears unreliable as an indicator of phylogenetic relationships (Fishbein 2001; Goyder et al. 2007).

Bullock (1952, 1953a, b, 1955, 1956, 1957, 1961) and later workers (Kupicha 1984; Smith 1988; Goyder 1995, 1998a, b, 2001, 2005; Goyder & Nicholas 2001) have attempted to reunite groups of species separated arbitrarily by Brown’s (1902) treatment. In doing so, increased significance has been attached to vegetative characters at the expense of coronal morphology. The core genera of Asclepiadinae currently recognised in tropical Africa are as follows: Asclepias, Aspidoglossum E. Mey., Glossostelma Schltr., Gomphocarpus R. Br., Margaretta, Odontostelma Rendle, Pachycarpus, Stathmostelma K. Schum., Stenostelma Schltr., Trachycalymma (K. Schum.) Bullock and Xysmalobium. The monotypic Aidomene Stopp was recently reduced to synonymy under Asclepias aurea (Schltr.) Schltr. (Goyder et al. 2008). Additional species such as Schizoglossum alpestre K. Schum. or Stathmostelma verdickii De Wild. are currently unplaced, having been excluded from genera as they were revised (Kupicha 1984; Goyder 1998b). Many African species described in Asclepias were never reassigned to segregate genera despite Bullock’s intention to restrict Asclepias to species from the New World.

Insights from the first molecular study of the subtribe (Goyder et al. 2007), although limited by incomplete sampling and poor resolution, suggest that the genera as currently defined map poorly onto cladograms illustrating their inferred evolutionary history. Our phylogenetic understanding of this group of plants is inadequate for confident redefinition of generic limits, or to indicate which morphological characters might provide the best indicators of phylogenetic relationship. Although species of Margaretta and Stathmostelma are undoubtedly closely allied (Goyder et al. 2007: 431, Fig. 1), it is not at all clear from available evidence what other species might also group with them. Asclepias inaequalis Goyder, described below, appeared (as ‘Gen. indet. aff. Asclepias’) in a well-supported clade with Stathmostelma and Margaretta in Goyder et al. (2007). However, several of the other tropical species of Asclepias share some physical characteristics with these plants and might, or might not, be related genetically. I have therefore refrained at this stage from formally uniting Margaretta with Stathmostelma. More comprehensive molecular surveys of the Asclepias radiation led by Mark Fishbein at Portland State University, in collaboration with David Chuba for Old World species, have also been hampered by lack of resolution and show little sign of resolving these issues (Fishbein, pers. comm.). In the light of this, the most conservative approach is to retain Asclepias as the generic name for species of uncertain affinity, as a broad definition of the genus would include the entire radiation except for Calotropis R. Br., Kanahia R. Br. and Pergularia L. A more narrowly defined Asclepias appears not to be monophyletic, with both New World (Asclepias sensu stricto) and Old World radiations, but there is currently no workable hypothesis for assigning Old World species to other genera.

Fig. 1

A – C Asclepias stathmostelmoides. A habit; B fruit; C flower. D A. longissima, flower, with detail of coronal papillae. E A. crassicoronata, flower. F A. tanganyikensis, flower. A & C from Bidgood et al. 2647; B from Congdon s.n.; D from Johnston 257; E from Bidgood et al. 2388; F from Lynes IH 90. drawn by margaret tebbs.

It is disappointing, then, in this precursor to the Apocynaceae accounts for the Flora of Tropical East Africa and Flora Zambesiaca, to have to resort to a broad, almost certainly paraphyletic concept of Asclepias to accommodate species excluded from other genera, and species of uncertain affinity. Asclepias in this sense contains so much morphological variation that I can no longer justify the maintenance of Trachycalymma (Goyder 2001), with its highly derived coronas, or Odontostelma, as distinct genera.

For the purposes of this contribution, tropical Africa is taken to be subsaharan Africa as far south as Angola and the countries of the Flora Zambesiaca region (Mozambique, Malawi, Zambia, Zimbabwe, Botswana and the Caprivi Strip of Namibia). Thirty-eight species of Asclepias occur in the region. A synopsis is presented, with nine species and one subspecies described for the first time. The inclusion of Trachycalymma again within Asclepias requires four new nomenclatural combinations. A further three new names and combinations are required to validate the transfer of Odontostelma welwitschii Rendle, Schizoglossum alpestre and Stathmostelma verdickii to Asclepias.

Material

The study was based principally on collections housed at BM, BR, EA and K, with some additional material from E, LISC, LMU, MAL, MO, MPU, P, PRE and SRGH.

Geographic Distribution and Endemism in Tropical Africa

In tropical Africa the core genera of Asclepiadinae, the ‘Asclepias radiation’, contain some 125 species. Within Asclepias itself, as defined here, one neotropical species, Asclepias curassavica L., has become naturalised in wetter parts of tropical Africa. The remaining 37 species are all native and endemic to continental Africa. The montane regions of southern Tanzania, northern Malawi and the Katanga highlands of south-eastern Democratic Republic of Congo appear to be a centre of diversity not only for Asclepias, with 14 species, but for some other genera of the African Asclepias radiation. Some high altitude species are restricted to particular mountain blocks. The Ufipa highlands between Lake Tanganyika and Lake Rukwa in SW Tanzania have the endemic taxa Asclepias pseudoamabilis Goyder, Glossostelma mbisiense Goyder, Margaretta rosea Oliv. subsp. corallina Goyder and Pachycarpus pachyglossus Goyder, while the Kitulo Plateau and adjacent ranges N of Lake Malawi are home to A. alpestris, A. breviantherae Goyder subsp. minor Goyder, A. edentata Goyder, A. inaequalis, A. mtorwiensis Goyder and P. grantii (Oliv.) Bullock subsp. marroninus Goyder and P. richardsiae Goyder. Most other taxa are more widespread, frequently at lower altitudes. Several species, such as A. densiflora N. E. Br., A. adscendens (Schltr.) Schltr., A. meliodora (Schltr.) Schltr. and A. eminens (Harv.) Schltr., are predominantly southern African in affinity and distribution. Two species, A. solstitialis A. Chev. and A. kamerunensis Schltr. occur in West Africa.

Key to Genera of Asclepiadinae in Tropical Africa

• 1. Plants twining; leaves suborbicular with deeply cordate base; staminal corona lobes drawn out into prominent apical and basal projections; follicles frequently paired . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pergularia

• 1. Plants self-supporting, branches prostrate or erect, never twining; leaves linear to oblong or ovate, never suborbicular; staminal corona lobes lacking apical and basal projections; follicles almost always solitary . . . . . . . . . . . . . . . . . . . . . . . 2

  • 2. Staminal corona with basal spur; moderate to large arborescent shrubs . . . . . . . . . . . . . . . . . . . . . . . . Calotropis

  • 2. Staminal corona lacking basal spur; slender to robust herbs or subshrubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

    • 3. Inflorescence axis indeterminate; rheophyte in seasonal watercourses . . . . . . . . . . . . . . . . . . . . . . . . Kanahia

    • 3. Inflorescence umbelliform, sometimes subglobose, the axis determinate; occuring in various habitats including seasonally waterlogged grasslands or banks of rivers, but not the river bed . . . . . . . . . . . . . . . 4

      • 4. Inflorescence a sessile or shortly pedunculate globose umbel; corolla appearing subglobose, the lobes concave in lower half, recurved above; corona with erect subulate tips well-exserted beyond mouth of corolla (mostly southern Africa) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stenostelma

      • 4. Inflorescence and flowers not as above. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 5

        • 5. Inflorescences sessile and fasciculate; pollinia with transparent germination zone at point of attachment to translator arms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Aspidoglossum

        • 5. Inflorescences pedunculate or rarely sessile; pollinia lacking transparent germination zone. . . . . . . . . 6

          • 6. Short-lived perennial subshrubs or pyrophytic herbs; rootstock a conventional taproot, sometimes becoming woody (especially in pyrophytes), but not swollen to form a napiform tuber . . . . . . . 7

            • 7. Corona laterally compressed, with a central cavity; leaves glabrous or with soft indumentum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gomphocarpus

            • 7. Corona solid, fleshy, without a central cavity; leaves with stiff, ± hispid indumentum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . Xysmalobium (X. undulatum)

          • 6. Pyrophytic herbs; rootstock a vertical napiform tuber and/or with fleshy fusiform lateral roots . . . . . . . . . . 8

            • 8. Leaves with an indumentum of stiff hairs, feeling scabrid to the touch; lamina generally broad with prominent secondary veins and a truncate to cordate base; follicles generally ornamented with longitudinal wings or soft spine-like processes (but smooth and inflated in Pachycarpus lineolatus and P. bisacculatus) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

              • 9. Corona lobes solid, fleshy; corolla usually bearded within towards the apex; follicles covered with soft filiform processes . . . . . . . . . . . . . . . . . . . . . . . Xysmalobium (X. undulatum)

              • 9. Corona lobes generally dorsiventrally flattened, commonly with lobes or fleshy wings arising near the base of the ventral face; corolla not conspicuously bearded; follicles winged or smooth, lacking filiform processes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pachycarpus

            • 8. Leaves glabrous or pubescent, if stiff scabrid hairs present, then confined to the margins; lamina narrow to broad, secondary veins often obscure, base frequently cuneate, occasionally truncate or cordate; follicles generally smooth, rarely with weak ornamentation of short filiform processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

              • 10. Corona lobes solid, fleshy, occasionally with teeth or small processes apically (but laminar in Glossostelma carsonii) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

                • 11. Rootstock with a short vertical axis from which fusiform lateral tuberous roots arise; leaves semisucculent, venation obscure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Glossostelma

                • 11. Rootstock a vertical napiform tuber; leaves membranous, venation mostly easily observed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Xysmalobium

              • 10. Corona lobes laminar or cucullate, with or without teeth or other ornamentation within the cavity of the lobe, sometimes somewhat reduced . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

                • 12. Corona lobes petaloid, larger and more showy than the corolla. . . . . . . . . . . . . . Margaretta

                • 12. Corona lobes not petaloid . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

                  • 13. Pollinaria with differentially winged and contorted translator arms: proximal portion broad and membranous, distal portion filiform and pendulous; corolla and corona generally brightly coloured (red, orange, yellow), occasionally white with purple markings; flowers held erect . . . . . . . . . . . . . . . Stathmostelma

                  • 13. Pollinaria not as above; corolla and corona dull, if brightly coloured then corona with prominent tooth arising from the cavity, or flowers nodding or held laterally . . . Asclepias

Synopsis of Asclepias in Tropical Africa

Asclepias L. (1753: 214). Type species: A. syriaca L. (lectotype designated by Hitchcock in Hitchcock & Green 1929: 136 (see also Jarvis 2007: 322)).

Odontostelma Rendle (1894: 161). Type species: O. welwitschii Rendle.

Trachycalymma (K. Schum.) Bullock (1953b: 348). Type species: T. cristatum (Decne.) Bullock.

Aidomene Stopp (1967: 21). Type species: A. parvula Stopp.

Slender to robust perennial herbs with annual stems arising from a tuber or fleshy taproot; latex white; stems prostrate to erect, simple or branched. Leaves opposite, linear to broadly ovate. Inflorescences terminal or extra-axillary, nodding or erect, umbelliform, sessile or pedunculate. Flowers 5-merous. Corolla divided almost to the base, lobes campanulate, spreading or reflexed. Corolline corona absent. Gynostegial corona of 5 generally cucullate fleshy lobes arising from the staminal column in a staminal position; minute interstaminal lobes sometimes also present. Pollinia pendant in anther cells; translator arms slender and terete or flattened, sometimes clearly geniculate, but never with a massively expanded proximal portion and slender distal portion. Stylar head rarely projecting much beyond top of anthers (but long-rostrate in Asclepias longirostra). Follicles mostly single by abortion, generally held erect, smooth, occasionally ribbed or with lines of soft pubescent processes. Seeds ovate, discoid, with a coma of silky hairs.

A genus with two major centres of distribution, one New World with c. 120 spp mostly centred on southern parts of the North American continent, the other Old World, with c. 80 spp, 38 of these in tropical Africa with the remainder in southern Africa. In addition, many segregate genera have been recognised in the Old World. In the broad sense the Asclepias radiation comprises some 380 – 400 species.

note: Only generic synonyms relevant to the Old World have been cited above.

In the synopsis below, only specimens from tropical Africa have been cited, although an outline of the overall geographic distribution is presented. Distributions within countries follow the major divisions recognised by the three principal regional Floras for tropical Africa — Flore d’Afrique Centrale, Flora of Tropical East Africa and Flora Zambesiaca. Preliminary conservations assessments are made using version 3.1 of the IUCN Red List Categories and Criteria (IUCN 2001).

Key to Species

• 1. Corolla bright red; corona orange or yellow, with prominent tooth arising from the cavity and arching over the stylar head; annual or short-lived perennial from fibrous, non-tuberous rootstock; pan-tropical weed . . . . 1. curassavica

• 1. Corolla white, yellow, green or brownish; corona variously coloured, corona tooth absent or inconspicuous and included within the cavity of the lobe; perennial producing annual shoots from tuberous rootstock; plants native to tropical Africa

  • 2. Leaves absent or rudimentary in upper, fertile part of stem; flowers ± sessile . . . . . . . . . . . . . . . . 19. minutiflora

  • 2. Upper portion of stem with fully developed leaves; flowers clearly pedicellate

    • 3. Inflorescences erect

      • 4. Inflorescences solitary and terminal

        • 5. Corona lobes about as tall as the column, less than 3 mm long

          • 6. All leaves narrowly linear with an attenuate base, glabrous or subglabrous; inflorescence with 5 – 10 flowers, corolla campanulate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24. nuttii

          • 6. At least the lower leaves triangular with a truncate to weakly cordate base, pubescent; inflorescence with 10 – 35 flowers. corolla somewhat reflexed

            • 7. Peduncle less than 5 cm long, inflorescences with 10 – 20 flowers; follicles with discrete, soft, spine-like processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37. adscendens

            • 7. Peduncle at least 8 cm long, inflorescences with 10 – 35 flowers; follicles with irregularly lobed longitudinal wings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36. densiflora

        • 5. Corona lobes twice as long as the column, at least 5 mm long

          • 8. Proximal margins of corona lobes twice as tall as column, central tooth only marginally longer than the proximal margins; anther wings triangular above the conspicuous notch, curved below it . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23. eminens

          • 8. Proximal margins of corona lobes ± as tall as column, distal margin forming a tooth twice as long; anther wings triangular, without a conspicuous notch, lower margins not curved . . . . . . . . 32. grandirandii

      • 4. Inflorescences extra-axillary, sometimes initially appearing terminal

        • 9. Corona shorter than, or about as tall as the column

          • 10. Anther wings c. 2 mm long, the margins with a conspicuous notch towards the base, rounded abruptly beneath the notch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25. occidentalis

          • 10. Anther wings at most 1.5 mm long, margins without a conspicuous basal notch

            • 11. Outer face of corolla glabrous

              • 12. Corona lobes ± as tall as column, pouched, with apical and marginal lobules; Tanzania (Kipengere mts) at high altitude . . . . . . . . . . . . . . . . . . . . . . . . . 28. mtorwiensis

              • 12. Corona lobes less than half height of column, not pouched, and with fleshy peg on inner face; seasonally waterlogged plateau grasslands from Angola to Zimbabwe . . . 29. minor

            • 11. Outer face of corolla pubescent

              • 13. Corona 2 – 4 mm long, laterally compressed, the apex drawn out into an erect tooth; leaves narrowly linear, base cuneate; Zimbabwe and Mozambique . . . . . . 34. cucullata

              • 13. Corona c. 1.5 mm long, neither laterally compressed nor with an apical tooth — pouched and with 2 rounded auricles apically; leaves linear to oblong, narrowing abruptly at the base; southern Tanzania and northern Malawi . . . . . . . . . . . . 27. A. breviantherae

        • 9. Corona clearly longer than the column

          • 14. Corona lobes dorsiventally flattened, broadly obovate . . . . . . . . . . . . . . . . . . . . . . . . . 26. inaequalis

          • 14. Corona lobes cucullate, or if dorsiventrally flattened then broadest near the base

            • 15. Leaves narrowly to broadly oblong, secondary veins clearly visible

              • 16. Corona lobes with mid-line drawn out into a long-attenuate tip, 5 – 7 mm long; outer face of corolla pubescent; highlands of SE Congo, SW Tanzania, NE Zambia and northern Malawi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32. grandirandii

              • 16. Corona lobes lacking long drawn-out tip, 3 – 4 mm long; outer face of corolla glabrous; regions of Botswana and Mozambique bordering South Africa and Swaziland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38. meliodora

            • 15. Leaves narrowly linear, only the mid-vein visible

              • 17. Corona with well-developed attenuate appendage on adaxial face; found only above 2500 m in the Kitulo and Kipengere mountains of southern Tanzania . . . . . . . . . . . . . . . . 30. alpestris

              • 17. Corona lacking an adaxial appendage

                • 18. Peduncles mostly 5 – 15 cm long, subglabrous or minutely pubescent; corolla yellow, cream or white adaxially; corona lobes lacking papillae in the cavity and along the midline; stems reddish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33. aurea

                • 18. Peduncles 1 – 4 cm long, densely pubescent, sometimes minutely so; corolla greenish white tinged pink adaxially; corona lobes papillose in the cavity and/or along the midline; stems green

                  • 19. Corona lobes 3 – 3.5 mm long, papillae present in both cavity of lobe and on midline; translator arms of uniform thickness . . . . . . . . . . . . . . . . . . . . . . . . 35. pygmaea

                  • 19. Corona lobes 4 – 8 mm long, papillae present only along the midline; translator arms broader distally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31. randii

    • 3. Inflorescences nodding

      • 20. Leaves ovate or broadly oblong, generally with a truncate to cordate base

        • 21. Leaves semisucculent, glabrous or subglabrous; venation usually indistinct

          • 22. Corona lobes laterally compressed and with a central cavity. . . . . . . . . . . . . . . . . . . . . . .12. fulva

          • 22. Corona lobes dorsiventrally flattened, at least distally; margins inrolled, but not forming a distinct central cavity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18. buchwaldii

        • 21. Leaves herbaceous, pubescent; venation prominent

          • 23. Corona lobes with a fimbriate tooth in the cavity; anther wings c. 2.5 mm long; plants of southern Ethiopia. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15. pseudofimbriata

          • 23. Corona lobes without a tooth in the cavity; anther wings c. 1.5 mm long; plants of the eastern Zimbabwe-Mozambique highlands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14. fimbriata

      • 20. Leaves linear to lanceolate, tapering gradually into the petiole or with a narrowly truncate base

        • 24. Stylar head extending c. 5 mm beyond anthers as a long-rostrate appendage . . . . . . . . . 11. longirostra

        • 24. Stylar head not or barely extending beyond anthers, flat or domed

          • 25. Corona lobes spreading from the column, subcylindrical with densely papillate inrolled upper margins; endemic to Chimanimani mts (eastern Zimbabwe). . . . . . . . . . . . . . 16. graminifolia

          • 25. Corona not as above

            • 26. Plant generally taller than 50 cm; most leaves more than 10 cm long

              • 27. Corona lobes 7 – 10 mm long, twice the height of the column; corolla lobes at least 7 mm long; sepals at least 8 mm long. . . . . . . . . . . . . . . . . . . . . . . . . . . 2. stathmostelmoides

              • 27. Corona lobes less than 7 mm long, 1 – 1.5 times height of column; corolla lobes 6 mm or less; sepals at most 6 mm long

                • 28. Corona lobes 4 – 7 mm long; anther wings 2.5 – 3 mm long

                  • 29. Upper margins of corona highest proximally, rounded and densely papillate; outer face of corolla pubescent; inflorescences with fewer than 5 flowers; Tanzania, Mozambique and Zambia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. longissima

                  • 29. Upper margins of corona raised distally, with a prominent tooth pointing towards column at about the mid point; outer face of corolla glabrous; inflorescences with at least 10 flowers; West Africa . . . . . . . . . . . . . . . . . . . . . . 6. solstitialis

                • 28. Corona lobes 2 – 3.5 mm; anther wings no more than 2 mm long

                  • 30. Peduncles to 1.5 cm long; anther wings with curved margins; corona fleshy, not laterally compressed, with a pair of acute teeth 0.5 – 1 mm long on the proximal margins and a fleshy tooth on the distal margin all pointing towards head of column. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. crassicoronata

                  • 30. Peduncles at least 2 cm long; anther wings triangular; corona lobes laterally compressed, with tooth half way along upper margin

                    • 31. Corona lobes taller than broad; anther wings 1.5 – 2 mm long; W Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. kamerunensis

                    • 31. Corona lobes ± as broad as tall; anther wings 1 mm long; southern Tanzania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. tanganyikensis

            • 26. Plant generally shorter than 50 cm; most leaves less than 10 cm long

              • 32. Corona lobes laterally compressed for their entire length, not drawn out into a tongue distally

                • 33. Corolla lobes 4 – 6 mm long, green or blue outside, glabrous; corona lobes taller than broad; W Africa. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. kamerunensis

                • 33. Corolla lobes (6 –) 7 – 9 mm long, tinged with red, brown or purple outside, pubescent at least towards the tip; corona lobes taller than broad or about as broad as tall; Katanga plateaus, southern Tanzania, Zambia and Malawi (amabilis complex)

                  • 34. Leaves densely pubescent with spreading white hairs on both sides; corona lobes taller than broad. . . . . . . . . . . . . . . . . . . . . . . . . . 10. pseudoamabilis

                  • 34. Leaves glabrous or minutely rusty pubescent; corona lobes as broad as tall

                    • 35. Corona lobes variously lobed or toothed on upper margins, outer margins fused; growing in seasonally waterlogged grassland . . . . . . . . 8. amabilis

                    • 35. Corona lobes lacking teeth on the upper margins, outer margins free; found in montane grassland . . . . . . . . . . . . . . . . . . . . . . . . . 9. edentata

              • 32. Corona lobes rounded in section or dorsiventrally flattened, if appearing laterally compressed near attachment to column, then distal margins drawn out into a tongue

                • 36. Corona lobes subglobose; a tuft of papillae entirely filling the cavity of the corona . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13. palustris

                • 36. Corona lobes generally longer than broad; papillae, if present, microscopic

                  • 37. Gynostegium stipitate, the stipe 2 – 3.5 mm long; free portion of corona lobes forming an erect dorsiventrally flattened tongue 4 – 5 mm long with a truncate apex and inrolled margins . . . . . . . . . . . . . . . . . . 18. buchwaldii

                  • 37. Gynostegium sessile; corona lobes not as above

                    • 38. Corona lobes narrowing abruptly near the base to form a curved or pouched tongue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17. shabaensis

                    • 38. Corona lobes tapering gradually into the tongue

                      • 39. Corolla white, frequently suffused with pink or purple, but never strongly veined; anther wings c. 1.5 mm long; proximal margins of corona lobes reaching ± halfway up anther wings . . . . . . 22. foliosa

                      • 39. Corolla white or pink with deeper veins within; anther wings c. 2 mm long; corona lobes with proximal margins not reaching base of anther wings

                        • 40. Leaves mostly linear; corona lobes purple with pale margins, 5 – 7 mm long; coronal papillae in a band across the extreme base of the lobe . . . . . . . . . . . . . . . . . . . . . . . . . 21. schumanniana

                        • 40. Leaves mostly oblong or elliptic; corona lobes white with pink at base, 4 – 5 mm long; coronal papillae in a band across the middle of the lobe . . . . . . . . . . . . . . . . . . . . . . . . . . 20. ameliae

1. Asclepias curassavica L. (1753: 215). Type: Curaçao, Linn. Herb. 310: 19 (lectotype LINN, designated by Woodson 1954: 59 (see also Jarvis 2007: 321)).

Asclepias nivea var. curassavica (L.) Kuntze (1891: 418).

Asclepias bicolor Moench (1794: 717), nom illegit. Type as for A. curassavica L.

Asclepias aurantiaca Salisb. (1796: 150), nom illegit. Type as for A. curassavica L.

Asclepias margaritacea Hoffmanns. ex Schult. (1820: 86). Type: Brazil, Camete, Hoffmannseg s.n. (not traced).

Asclepias cubensis Wender. (1843: 830). Type: Cuba, Jan. 1841, Pfeiffer s.n. (?MAR† (Stafleu & Cowan 1988: 178)).

Asclepias curassavica var. concolor Krug & Urb. (1899: 389). Type: Puerto Rico, Sintennis 3949 (lectotype MO, designated here, see below). [Paralectotypes: Santo Domingo, near Puerto Plata, 1849, Schwanecke s.n. (B†); Puerto Rico, near Bayamon, Sintennis 67c (B†) & Cabo Rojo, Stahl 713 (B†).]

Distribution. A pantropical weed. Native and widespread across the neotropics, cultivated and naturalised widely in Old World tropics.

Selected Specimens. Sierra Leone. Freetown, growing between the laterite rocks at Lower Commisariat, Aug. 1915, Litchford s.n. in Lane-Poole 384 (K). Ghana. Aburi, Johnson s.n. (K). Nigeria. Old Idanre, 27 Nov. 1983, Lowe 4448 (K). Equatorial Guinea. Bioko [Fernando Po], Dec. 1859, Mann 48 (K); Annobón [Pagalú], Lago a Pot, 5 Nov. 1987, Carvalho 3072 (K). São Tomé & Príncipe. São Tomé, near the waterfall of Manuel Jorge R., 20 Oct. 1993, Figueredo & Arriegas 60 (K). Gabon. Mitzic, 31 July 1957, Jeffrey 327 (K). Dem. Rep. Congo. VI: Barumbu, 30 Oct. 1913, Becquaert 1042 (K). Uganda. U2: Toro Distr., Ibonde, camp garden, 13 Aug. 1938, Thomas 2341 (K). Kenya. K7: Kilifi Distr., Kibarani [Kiborani], 28 Sept. 1945, Jeffery K332 (K). Tanzania. T3: Tanga Distr., Usambara, Heinsen 129 (K); Lushoto Distr., nursery, E African Agricultural Research Station Amani, 5 April 1932, Greenway 2961 (K); T7: Mbeya Distr., gardens of the Mt Livingstone Hotel, Mbeya, 29 Nov. 1994, Goyder et al. 3841 (DSM, K). Zanzibar, 1927, Toms 16 (K). Mozambique. T: Zumbo, on the Zambezi, 22 June 1900, Baum 1004 (K); M: Maputo [Lourenço Marques], Jardim Vasco da Gama, 20 March 1972, Balsinhas 2400 (K). Malawi. S: Blantyre, on waste ground in township, 6 Jan. 1956, Jackson 1774 (K). Zimbabwe. W: Hwange [Wankie] Distr., Matetsi Safari area, Namakuwe R, 13 March 1981, Gonde 360 (K, SRGH).

Habitat. Moist areas.

Conservation Status. Least Concern (LC).

Notes. Synonymy for this species follows Woodson (1954), amended as appropriate. In formally designating a lectotype for Asclepias curassavica var. concolor I have followed Woodson (1954: 59) who stated that Sintennis 3949 (MO) was the type of this name.

2. Asclepias stathmostelmoides Goyder nom. nov. Fig. 1A – C.

Stathmostelma verdickii De Wild., Ann. Mus. Congo Belge. Bot., sér. 5, 1: 188 (1904), non Asclepias verdickii De Wild. (1906: 305). Type: Democratic Republic of Congo, Katanga, Feb. 1900, Verdick 361 (holotype BR, photo. K).

Distribution. Scattered localities in Burundi, Democratic Republic of Congo, Tanzania, Zambia, Malawi and Mozambique.

Selected Specimens. Burundi. IX: Bururi Distr., Nyanza Lake, Makamba road, 19 March 1967, Lewalle 1716 (BR). Dem. Rep. Congo. V: Lomami, Mwene Ditu, May 1952, Dandoy 227 (BR, K); IX: West of Lake Kivu, 16 July 1908, Kassner 3808 (P); XI: Katanga Distr., Mulombo, Feb. 1900, Verdick 361 (BR). Tanzania. T1: Mwanza Distr., 60 km S of Nungwe, SW of Lake Victoria, 18 Dec. 1936, Morgan 72 (BM); T4: Nkansi Distr., 29 km on Namanyere – Karonga road, 5 March 1994, Bidgood et al. 2647 (EA, K); T5: Singida Distr., Matalele, 22 March 1928, Burtt 1422 (K); T7: Mbeya Distr., Magangwe air strip, 14 April 1970, Park Ranger s.n. in EAH 14434 (EA, K). Zambia. N: Mbala Distr., Chilongowelo, close to path to Plain of Death, 4 Feb. 1952, Richards 951 (K); C: Mulungushi, 9 Feb. 1964, Fanshawe 8268 (K); S: Mazabuka Distr., Mapanza, 15 Feb. 1958, Robinson 2760 (K, SRGH). Malawi. N: Mbawa experimental station, Mzimba, fr. 5 April 1955, Jackson 1598 (K); S: Liwonde National Park, Chiunguni Horseshoe, 29 Dec. 1986, Oudley 1806 (K). Mozambique. Z: Gurue, 26 km from Mutuali to Lioma, 10 Feb. 1964, Torre & Paiva 10505 (LISC).

Habitat. Grassland and open Brachystegia or other deciduous woodland; 500 – 1500 m.

Conservation Status. Least Concern (LC).

Notes. Bullock (1953b: 346), who saw only the type, allied this species with Stathmostelma welwitschii, to which it bears little similarity. The hispid indumentum and apparently tuberous rootstock may explain the former placement of this species within Stathmostelma, but other characters are anomalous for that genus. The flowers are nodding rather than erect; the corona very similar to that of Gomphocarpus integer — as pointed out by De Wildeman (1904) — but questioned by Bullock (1953b: 347); the anther wings are straight, not curved as in Stathmostelma; and the translator arms are not developed in the flattened and contorted style so characteristic of that genus. This species was excluded from Stathmostelma by Goyder (1998b: 614).

3. Asclepias longissima (K. Schum.) N. E. Br. (1902: 338). Type: Tanzania, Lake Malawi [Nyasa], Goetze s.n. (holotype B†; isotype K). Fig. 1D.

Gomphocarpus longissimus K. Schum. (1901: 382).

Distribution. Known from several localities in SW Tanzania, Niassa Province in Mozambique, and around Mbala in northern Zambia.

Selected Specimens. Tanzania. T4: Ufipa Distr.: escarpment above Kasanga, 30 March 1959, Webster s.n. in Richards 11018 (K); T7: Rungwe Distr.: Kyimbila, 4 March 1914, Stolz 2579 (K); T8: Songea Distr.: between the two crossings of the R. Luhekea at foot of Mbamba Bay escarpment, 6 April 1956, Milne-Redhead & Taylor 9484 (K). Zambia. N: Mbala Distr., Old road from Chemba village to Cascalawa, 16 Feb. 1960, Richards 12490 (K, SRGH); Mbala [Abercorn] Distr., April 1932, Gamwell 111 (BM). Mozambique. N: Marrupa, 20 km from Missor on Lichinga road, 16 Feb. 1981, Nuvunga 534 (K, LMU).

Habitat. Generally on rocky ground in open Brachystegia woodland or grassland; 500 – 1500 m.

Conservation Status. Least Concern (LC).

4. Asclepias crassicoronata Goyder sp. nov. A. stathmostelmoidi atque A. longissimo atque A. tanganyikensi similis sed lobis coronae ecucullatis carnosis dentes introrsos ferentibus et floribus minoribus differt. Typus: Zambia N, 30 km ESE of Kasama, 18 Feb. 1961, Robinson 4390 (holotypus K).

Perennial herb with a single annual stem arising from a tuber or fleshy taproot; stems c. 1 m long, unbranched, erect, glabrous or minutely pubescent above, lacking leaves in upper parts. Leaves with petiole 1 – 5 mm long; lamina 11 – 20 × 0.3 – 0.4 cm, narrowly linear, apex attenuate, the base cuneate, secondary veins inconspicuous, margins revolute, glabrous except along margins. Inflorescences extra-axillary with 4 – 6 flowers in a nodding umbel, peduncles 0.5 – 1.5 cm long, minutely pubescent; pedicels 1.5 – 2 cm long, slender, minutely pubescent. Sepals 2 – 3 × 1 mm, triangular, acute, pubescent. Corolla strongly reflexed, green or purple, glabrous or sparsely pubescent on outer surface, minutely papillate within; lobes 4 – 6 × 2 – 3 mm, ovate, acute, plane. Corona lobes attached c. 1 mm above the base of the staminal column, 3 – 3.5 × 1.5 mm, slightly taller than column, fleshy, concave above, not laterally compressed, with a pair of acute teeth 0.5 – 1 mm long on the proximal margins and a fleshy tooth on the distal margin all pointing towards head of column, green. Anther wings 1.5 mm long, curved; anther appendages c. 1 mm long. Corpusculum 0.5 × 0.2 mm, narrowly ovoid, brown; translator arms c. 0.3 mm long, flattened and slightly geniculate; pollinia c. 0.9 × 0.3 mm, flattened, obovate. Stylar head raised above top of anthers by c. 0.5 mm, flat. Follicles not seen. Fig. 1E.

Distribution. Known only from southern Tanzania (T4, T7), northern Zambia and central and northern Malawi.

Specimens Examined. Tanzania. T4: Ufipa Distr., Tatanda Mission, 22 Feb. 1994, Bidgood et al. 2388 (K); T7: Iringa Distr., Iheme, 30 km S of Iringa, 24 Feb. 1962, Polhill & Paulo 1591 (K); Mbeya Distr., between Mshewe and Muvwa villages, 2 Feb. 1990, Lovett et al. 4046 (K). Zambia . N: N Luangwa National Park, 16 Feb. 1994, Smith 244 (K); 30 km ESE of Kasama, 18 Feb. 1961, Robinson 4390 (K). Malawi. N: Mzimba, 28 Feb. 1959, Robson 1732 (K); Mzimba, 12 km S of Eutini, 31 Jan. 1976, Pawek 10780 (K, MAL); Vipya Plateau, 1948, Benson 1462 (BM); C: Chipala Hill, 6 km N of Kasungu, 14 Jan. 1959, Robson & Jackson 1182 (K).

Habitat. Brachystegia or mixed deciduous woodland on rocky hills; 1000 – 1900 m.

Conservation Status. Least Concern (LC).

Notes. The flowers of this species are smaller than the similar Asclepias stathmostelmoides, A. longissima and A. tanganyikensis, and the corona is not laterally compressed and cucullate, but fleshy and with an inward-pointing tooth.

5. Asclepias tanganyikensis E. A. Bruce (1934: 303). Type: Tanzania, Iringa, Mt Luhoto [Lukota], 12 Feb. 1932, Lynes Ih 90 (holotype EA, not seen; isotype K). Fig. 1F.

Gomphocarpus tanganyikensis (E. A. Bruce) Bullock (1953b: 340).

Distribution. Known only from two collections near Iringa in southern Tanzania.

Specimens Examined. Tanzania. T7: Iringa Distr.: Mt Luhoto [Lukota], 12 Feb. 1932, Lynes Ih 90 (K); Signal Hill, 20 Feb. 1932, St Clair Thompson 468 (BM, K) [but note that flower in packet and the drawing on the K sheet are not from this collection but from Asclepias crassicoronata described above].

Habitat. Thompson 468 records the following: ‘Frequent and gregarious in poor soil under Brachystegia’; 1700 – 1800 m.

Conservation Status. Endangered EN B2ab(iii). The area around Iringa is under considerable pressure due to increases in population and cultivation. Asclepias tanganyikensis is known historically from just two localities, and has not been collected since 1932. It must be considered Endangered under Criterion B of the IUCN Red List Categories and Criteria (IUCN 2001) if it is not already Extinct.

Phenology. Flowering in February.

6. Asclepias solstitialis A. Chev. (1917: 270). Type: Ivory Coast, Cercle de Mankono, between Seguela and Tiana, 4 June 1909, Chevalier 21849 (holotype P, photo. K).

Gomphocarpus solstitialis (A. Chev.) Bullock (1953b: 340).

Distribution. Savannas of West Africa with a scattered distribution from the Guinea highlands to Cameroon.

Selected Specimens. Guinea (Conakry). Soarella, 22 June 1902, Pobéguin 1007 (K); Ziama, 10 May 1948, Adam 27210 (MO, PRE). Ivory Coast. Maharoue National Park, central savanna area, 19 May 1999, Jonkind & Diomaudé 4618 (K, WAG); nr Mankoro, Mont Kamoueniboka near Marabidyasa, 3 July 1909, Fleury s.n. in Chevalier 22017 (K, P). Ghana. Fesi, 13 Aug. 1969, Hall s.n. in GC 43198 (K). Nigeria. Aguji, near Ilorin, Thornton s.n. [recd. 26.8.1913] (K); Zungeru, 31 July 1905, Dalziel 3 (K). Cameroon. Mgoléré to Meiganga, June 1939, Jacques-Félix 4294 (K, P).

Habitat. Savanna grassland or woodland.

Conservation Status. Least Concern (LC).

notes. Flowers generally described as bluish on herbarium labels, but the descriptions are vague.

7. Asclepias kamerunensis Schltr. (1913: 137). Type: Cameroon, Kongola, April 1914, Mildbraed 9040 (neotype K, designated by Bullock 1953b: 340). Original syntypes: Cameroon, near Ngom, Oct. 1909, Ledermann 5663 (B†); S Adamaua, Mildbraed 4860 (B†).

Gomphocarpus kamerunensis (Schltr.) Bullock (1953b: 340).

Distribution. Savannas of west Africa with a scattered distribution from Ghana to Cameroon, Gabon and Central African Republic.

Selected Specimens. Ghana. Buem – Krachi Distr., Shiare, 18 April 1959, Hall 1448 (K). Nigeria. Onitsha Province, Nsuka, 24 June 1945, Thompson s.n. (K); Zaria Province, 5 km E of Mando, 8 June 1950, Keay s.n. in FHI 25857 (K). Cameroon. Bamenda, Ngong, June 1931, Maitland 1747 (K); Mbaw Plain, near Sabonbari village, 9 May 1962, Brunt 406 (K); near Laye, 30 km W of Batouri, 5 April 1962, Letouzey 4652 (K, P); Kongola, April 1914, Mildbraed 9040 (K). Central African Republic. Bozoum, 1 July 1931 & 1933, Tisserant s.n. in Le Testu 2855 (BM, 2 sheets).

Habitat. Grassland and open savanna woodland on rocky hills.

Conservation Status. Least Concern (LC).

Notes. Essentially a smaller, less glabrous version of Asclepias solstitialis. Flowers about half the size of the preceeding species.

8. Asclepias amabilis N. E. Br. (1895a: 70). Type: Zambia, Fwambo, Carson 55 (lectotype K, designated here). Paralectotype: Zambia, Fwambo, Carson 35 (K). Fig. 2C.

Fig. 2

A, B Asclepias pseudoamabilis. A habit; B flower. C A. amabilis, flower. D A. edentata, flower. A from Richards 6952 (above-ground portion) and Bullock 1947 (rootstock); B from Richards 6952; C from Richards 8029; D from Richards 7651. drawn by margaret tebbs.

Gomphocarpus amabilis (N. E. Br.) Bullock (1953b: 341).

Distribution. Recorded from southern Tanzania, northern Malawi, the Katanga plateaus of south-eastern Democratic Republic of Congo and the Mbala and Mwinilunga areas of Zambia.

Selected Specimens. D. R. Congo. XI: Biano Plateau, Kansenia stn, 8 Nov. 1958, Schmitz 6353 (BR); Kundelungu Plateau, 6.3 km N of Katshupa Post, 28 Jan. 1967, Malaisse 4963 (BR). Tanzania. T4: Ufipa Distr., 20 km from Kawimbe, 29 Jan. 1957, Richards 8029 (BR, K); Malonje Plateau, 3 Jan. 1962, Richards 15893 (K); T7: Chunya Distr., 80 km along Chunya – Itigi road, 21 March 1965, Richards 19785 (K); Mbeya Distr.: 8 km NE of Tunduma, 10 Jan. 1975, Brummitt & Polhill 13676 (K). Zambia. W: Mwinilunga Distr., Kalenda Plain N of Matonchi Farm, 8 Dec. 1937, Milne-Redhead 3556 (K); valley below Matonchi Farm, 19 Nov. 1962, Richards 17299 (K); N: Mbala Distr., Marsh near fish ponds, Kiwimbi, 9 Feb. 1955, Richards 4396 (BR, K); Lunzua Swamp, 17 Jan. 1962, Richards 15912 (K). Malawi. N: Rumpi Distr., Nyika Plateau, Lake Kaulime, 4 Jan. 1959, Richards 10459 (K); Katoto, 5 km W of Mzuzu, 10 Dec. 1977, Pawek 13279 (BR).

Habitat. Seasonally waterlogged grassland (dambo/mbuga); 1200 – 2300 m.

Conservation Status. Least Concern (LC).

Notes. Carson 55 was chosen as lectotype to avoid any possible confusion over the identity of the other syntype. Carson 35 from Fwambo in Zambia is a syntype of this name, but a collection with the same number, from an island in Lake Tanganyika, was described as Ceropegia constricta N. E. Br.

9. Asclepias edentata Goyder sp. nov. Ab A. amabili dentibus coronae carentibus (nec praesentibus), marginibus externis loborum coronae liberis (nec connatis), corolla atque corona viridibus (nec roseis neque purpurascentibus) differt. Typus: Tanzania T7, Njombe Distr., Kipengere Mts, 14 Jan. 1957, Richards 7774 (holotypus K, isotypus EA).

Perennial herb with a single annual stem, rootstock not seen; stems 0.2 – 0.4 m long, unbranched, erect, minutely pubescent above. Leaves sessile or with petiole to c. 5 mm; lamina 7 – 11 × 0.3 – 1 cm, narrowly linear to linear lanceolate, glabrous except on the midrib below. Inflorescences extra-axillary with 4 – 8 flowers in a nodding umbel, peduncles (2 –) 4.5 – 7 cm long, minutely pubescent; bracts to c. 0.8 cm long, filiform, pubescent; pedicels 1 – 2.5 cm long, minutely pubescent. Sepals c. 4 – 5 × 1.5 mm, lanceolate to narrowly triangular, attenuate, pubescent, generally reddish brown. Corolla reflexed, lobes 7 – 9 × 4 – 5 mm, ovate, subacute, adaxial surface green, minutely papillose, abaxial face dull brown or purple, sparsely pubescent, at least towards apex. Corona lobes attached 0.5 – 1 mm above the base of the staminal column, 3 – 4 × 3 – 4 mm, ± as tall as the column, laterally compressed, complicate, oblong but somewhat rounded, upper margins entire, slightly raised distally, then falling away to the base, only uniting near the base of the outer margin, green. Anther wings 1.6 – 1.8 (– 2) mm long, triangular. Corpusculum c. 0.35 × 0.15 mm, ovoid, brown, with narrow translucent flanges down the sides; translator arms c. 0.15 mm long, flattened and strongly geniculate; pollinia c. 0.9 × 0.25 mm, flattened, oblanceolate. Stylar head ± level with top of anthers. Follicles and seed not seen. Fig. 2D.

Distribution. Apparently restricted to the Kitulo and Kipengere mountains of southern Tanzania.

Specimens Examined. Tanzania. T7: Njombe Distr., Kipengere Mts, 10 Jan. 1957, Richards 7651 (K) & 14 Jan 1957, Richards 7774 (EA, K); Mbeya Distr., Kitulo Plateau, ridge E of Ishinga Mt summit, 9 Feb. 1979, Cribb et al. 11356 (K).

Habitat. Rough mountain grassland; 2500 – 2700 m.

Conservation Status. Endangered EN B1ab(iii). Much of the grassland on these mountain ranges has been severely degraded in recent years, and as the species is known from just two localities it must be considered Endangered under Criterion B of the IUCN Red List Categories and Criteria (IUCN 2001).

Notes. Asclepias edentata differs from A. amabilis in the absence of teeth on the corona, and the free outer margins of the corona lobes. Corolla and corona lobes are green in the new species, rather than pink or purplish in A. amabilis. Robinson 4174 (K) from northern Zambia is very similar to A. edentata but has a slightly distorted corona. It was collected at much lower altitude in woodland rather than montane grassland.

Asclepias edentata and the allied new species A. pseudoamabilis, are found in montane grassland, whereas A. amabilis is a plant of seasonally waterlogged dambos, generally at somewhat lower elevations. The altitude of 1500 m recorded on the label of Richards 7774 appears to be a typographic error for 2500 m, as Mary Richards’ collecting notebook at K has the altitude 8000 ft for this and neighbouring collections.

10. Asclepias pseudoamabilis Goyder sp. nov. A. edentatae similis sed lobis coronae longioribus quam latioribus, marginibus externis loborum coronae connatis (nec liberis), foliis utrinque dense pubescentibus (nec glabris neque subglabris) differt. Typus: Tanzania T4, Ufipa Distr., Mbisi, 27 Nov. 1949, Bullock 1947 (holotypus K).

Perennial herb with a single annual stem, arising from very deep seated rootstock (not seen); stems c. 0.3 m long, unbranched, erect, densely pubescent above. Leaves sessile or subsessile; lamina 5 – 9 × 0.5 – 1.5 cm, linear to lanceolate, densely pubescent with spreading white hairs on both surfaces. Inflorescences extra-axillary with 2 – 6 flowers in a nodding umbel, peduncles 2 – 4 cm long, densely pubescent; bracts to c. 0.6 cm long, filiform, pubescent; pedicels 1 – 2.5 cm long, densely pubescent. Sepals c. 4 – 5 × 1.5 mm, lanceolate to narrowly triangular, attenuate, densely pubescent, generally reddish brown. Corolla reflexed, lobes 7 – 9 × 4 – 6 mm, ovate, subacute, adaxial surface green, minutely papillose, pubescent towards margin, abaxial face dull brown or purple, densely pubescent. Corona lobes attached 0.5 – 1 mm above the base of the staminal column, 3 – 5 × 2 – 2.5 mm, taller than the column, laterally compressed, complicate, oblong and taller than wide, upper margins entire, slightly raised distally, then falling away and slightly recurved, fused along the outer margin, green. Anther wings 1.9 – 2.1 mm long, triangular. Corpusculum c. 0.4 × 0.1 mm, narrowly ovoid, brown, with narrow translucent flanges down the sides; translator arms c. 0.4 mm long, flattened and strongly geniculate; pollinia c. 1.2 × 0.25 mm, flattened, oblanceolate. Stylar head ± level with top of anthers. Follicles and seed not seen. Fig. 2A, B.

Distribution. Recorded only from the highlands around Sumbawanga and the volcanic Igwisi hills WNW of Tabora.

Specimens Examined. Tanzania. T4: Tabora Distr., Urambo, Igwisi Hill, 12 Dec. 1950, Moors K11 (K); Ufipa Distr., Mbisi, 27 Nov. 1949, Bullock 1947 (K) & 9 Nov. 1956, Richards 6952 (K); Ufipa Plateau overlooking Rukwa valley, top of Sakalilo Escarpment, 1 Dec. 1954, Richards 3496 (K); road from Muse Gap to Sumbawanga, 2 Sept. 1959, Richards 11410 (K).

Habitat. Very dry seasonally burnt grassland; mostly between 1700 – 2400 m, but down to c. 1100 m at Igwisi.

Conservation Status. Endangered EN B1ab(iii). With fewer than five localities, and degradation of habitat especially at lower altitudes, this species must be considered Endangered under Criterion B of the IUCN Red List Categories and Criteria (IUCN 2001). It may be significant that, in this generally well-collected area around Sumbawanga, the last record for the species was in 1959.

Notes. Essentially a pubescent form of the previous species, with additional differences in the corona. The corona lobes are taller than broad, the outer margins fused not free. Leaves are densely pubescent on both sides rather than glabrous or subglabrous in Asclepias edentata.

11. Asclepias longirostra Goyder sp. nov. Ab omnibus ceteris speciebus Asclepiadis africanis capitulo styli appendicem rostratam ferenti et appendicibus antherae erectis coronae similibus differt. Typus: Malawi, Fort Manning [Mchinji] Distr., near Tamanda Mission, 8 Jan. 1959, Robson 1105 (holotypus K).

Perennial herb with one or perhaps more annual stems arising from a slender woody taproot or tuber; stems 0.3 – 0.5 m long, unbranched, erect, subglabrous to minutely pubescent above. Leaves subsessile; lamina 5 – 7 × 0.1 – 0.3 cm, narrowly linear, glabrous. Inflorescences extra-axillary with 4 – 7 flowers in a nodding umbel, peduncles 2 – 6 cm long, glabrous; bracts c. 0.1 cm long, filiform; pedicels 0.5 – 1.5 cm long, glabrous or minutely rusty-pubescent. Sepals 3 – 4 × 1 – 1.5 mm, lanceolate to narrowly triangular, attenuate, glabrous or sparsely pubescent, reddish or purplish brown. Corolla campanulate, lobes 7 – 8 × 2 – 3 mm, ovate, with a long attenuate apex, adaxial surface green, minutely papillose, abaxial face dark purple, glabrous or minutely pubescent towards to apex. Corona lobes attached c. 0.5 mm above the base of the staminal column, 2 – 3 mm long, and slightly taller than the anthers, dorsiventrally compressed and ± oblong in outline, with the inflexed lateral margins produced above into short rounded teeth, somewhat fleshy, probably purple with white margins (see note below). Anther wings c. 1.5 mm long, triangular; anther appendages pale, narrowly triangular and drawn out into slender erect projections c. 3 mm long lying alongside the stylar head appendage. Corpusculum c. 0.4 × 0.1 mm, subcylindrical, dark brown, with narrow translucent flanges down the sides; translator arms c. 0.4 mm long, flattened and weakly geniculate with a short clasping overlap to the pollinia; pollinia c. 0.7 × 0.2 mm, flattened, ± oblong. Stylar head extending beyond top of anthers for c. 5 mm as a long, purple, rostrate appendage. Follicles and seed not seen. Fig. 3.

Fig. 3

Asclepias longirostra. A & B habit, with rootstock; C flower; D back of anther, with anther wings and long anther appendage. A & B from Robson 1105; C & D from Jackson 2295. drawn by margaret tebbs.

Distribution. Known only from two collections in north-central Malawi.

Specimens Examined. Malawi. C: Fort Manning [Mchinji] Distr., near Tamanda Mission, 8 Jan. 1959, Robson 1105 (K); N: Kapopo village, Chulu Native Authority, 15 Jan. 1959, Jackson 2295 (K).

Habitat. Seasonally waterlogged grassland — described by Jackson as a sandy seasonal swamp.

Conservation Status. Endangered EN B1ab(iii). Known from just two localities in an area with a growing population putting increasing areas into cultivation, this species must be considered Endangered under Criterion B of the IUCN Red List Categories and Criteria (IUCN 2001).

Notes. The rostrate stylar head appendage of this species appears to be unique in African Asclepias. The slender tips to the anther appendages look superficially like the teeth on the inner faces of staminal corona lobes seen in Aspidoglossum. Their derivation here, however, is quite different. Although highly distinctive, vegetative and floral characters other than the form of the stylar head and the anther appendages suggest a close affinity to Asclepias amabilis. Notes on both collections state that the ‘anther appendages’ are ‘purple tipped white’ or ‘dark purple edged white’ — these comments almost certainly refer to the corona lobes.

12. Asclepias fulva N. E. Br. (1895b: 254 (Oct. 1895)). Type: Uganda, Wilson 112 (holotype K).

Pachycarpus viridiflorus E. Mey. (1837: 214). Type: South Africa, Uitenhage Division, N side of the Zuurberg Mts, 2500 – 3000’, 30 Oct. 1829, Drège s.n. (holotype B†; isotype K).

Xysmalobium viridiflorum (E. Mey.) D. Dietr. (1840: 903).

Gomphocarpus viridiflorus (E. Mey.) Decne. (1844: 561).

Asclepias rubicunda Schltr. (1895b: 336 (Nov. 1895)). Types: Uganda, Buddu, February, Scott Elliot 7443 (lectotype K, designated here; isolectotype BM). Paralectotypes: Uganda, E side of Lake Albert Edward, August, Scott Elliot 8088 (BM, K).

Asclepias dregeana Schltr. (1895b: 337 (Nov. 1895)), nom. nov. for Gomphocarpus marginatus sensu Schltr., non E. Mey.

Asclepias calceolus S. Moore (1903: 312; Rand 1903: 338). Type: South Africa, Transvaal, open veld N of Johannesburg, Rand 966 (holotype BM; isotype K).

Asclepias dregeana Schltr. var. calceolus (S. Moore) N. E. Br. (1908: 697).

Asclepias dregeana Schltr. var. sordida N. E. Br. (1908: 697). Type: South Africa, Transkei, Kentani, Feb. 1905, Pegler 655 (holotype K; isotype PRE).

Pachycarpus fulvus (N. E. Br.) Bullock (1953b: 334).

Asclepias viridiflora (E. Mey.) Goyder (1997: 247), non A. viridiflora Raf. (1808: 360).

Distribution. Distributed from Uganda to eastern regions of South Africa and Lesotho.

Selected Specimens. Uganda. U2: Kigezi Distr., Nyakagyeme, April 1946, Pursglove 2042 (EA, K); U4: Masaka Distr., Buddu, Scott Elliot 7443 (BM, K). Kenya. K3: Uasin Gishu Distr.: Kipkarren, 1931, Brodhurst-Hill 57 (EA, K); S Elgon, May 1941, Tweedie 565 (K). Tanzania. T6: Morogoro Distr., Nguru Mts near Maskati Mission, 10 June 1978, Thulin & Mhoro 3152 (K); T7: Mbeya Distr., Poroto Mts, Ikuyu, 10 Feb. 1979, Cribb et al. 11375 (EA, K); T8: Songea Distr., 22 km SE of Songea, 26 March 1956, Milne-Redhead & Taylor 9341 (K). Zambia. N: Mbala [Abercorn] Distr., Ndundu, 16 Feb. 1957, Richards 8201 (K). Zimbabwe. N: Lomagundi Distr., Mtorashangu, Dec. 1973, Cannell 570 (K, SRGH); C: Makoni Distr., 1.5 km from Eagles Nest on Rusape road, 29 Nov. 1955, Drummond 5068 (K, PRE, SRGH); E: Mutare, S car park, Murahwa’s Hill, 1 Jan. 1965, Chase 8220 (EA, K, SRGH).

Habitat. Open grassland and Brachystegia or mixed deciduous woodland; 1000 – 2100 m.

Conservation Status. Least Concern (LC).

13. Asclepias palustris (K. Schum.) Schltr. (1895b: 336). Type: Angola, Malanje, Mechow 401 (lectotype K, designated by Goyder (2001: 134); B†). Paralectotype: Angola, Malanje, Mechow 317 (B†).

Gomphocarpus cristatus Decne. (1838: 325, t. 11D, Figs. 3 & 4), non Asclepias cristata S. Moore (1912: 343). Type: Angola, Benguela Plateau, da Silva s.n. (holotype P, photo K).

Fig. 4

A, B Asclepias occidentalis. A habit, with rootstock and single dehisced follicle; B flower. C, D A. mtorwiensis. C habit. D flower. A & B from Baldwin 14170; C & D from Brummitt et al. 18142. drawn by margaret tebbs.

Gomphocarpus paluster K. Schum. (1893: 127), as G. palustris.

Asclepias cristata S. Moore (1912: 343). Type: Angola, Kubango, Kapembe, 23 Nov. 1905, Gossweiler 2288 (lectotype BM (designated by Goyder 2001: 134). Paralectotype: Angola, near Forte Princeza Amelia, Dec. 1906, Gossweiler 4008 (BM).

Trachycalymma cristatum (Decne.) Bullock (1953b: 349).

[Asclepias kyimbilae Schltr. in sched. (Stolz 502 (K, WAG)).]

Distribution. Widely scattered in tropical Africa from Nigeria to Uganda in the north, and Angola to Zimbabwe in the south.

Selected Specimens. See specimens cited by Goyder (2001: 135) under Trachycalymma cristatum.

Habitat. Montane or seasonally waterlogged grassland, occasionally in open woodland; 1200 – 2600 m.

Conservation Status. Least Concern (LC).

14. Asclepias fimbriata Weim. (1935: 378). Type: Zimbabwe, Nyanga, above Pungwe stream, 16 Dec. 1930, Fries et al. 3748 (holotype LD, photo. K); isotypes BM, BR, SRGH).

Trachycalymma fimbriatum (Weim.) Bullock (1953b: 352).

Distribution. Known only from the eastern highlands of Zimbabwe and adjacent parts of Mozambique.

Selected Specimens. See specimens cited by Goyder (2001: 139) under Trachycalymma fimbriatum.

Habitat. Growing in open montane grassland; 1700 – 2300 m.

Conservation Status. Vulnerable VU B1ab(iii). Although known from several localities in the highlands of eastern Zimbabwe and as far as Mt Gorongosa in central Mozambique, many of the grasslands are becoming degraded as cultivation moves up the mountain slopes. The conservation status is therefore assessed as Vulnerable under Criterion B of the IUCN Red List Categories and Criteria (IUCN 2001).

15. Asclepias pseudofimbriata (Goyder) Goyder comb. nov.

Trachycalymma pseudofimbriatum Goyder, Kew Bull. 56: 139 (2001). Type: Ethiopia, Sidamo Region, Agere Selam, 12 Sept. 1990, Haugen 1503 (holotype K; isotype ETH).

Distribution. Known only from the Sidamo region of Ethiopia.

Specimens Examined. See specimens cited by Goyder (2001: 141) under Trachycalymma pseudofimbriatum.

Habitat. Growing in montane grassland; c. 2700 m.

Conservation Status. Endangered EN B1ab(iii). With fewer than five localities, which have been subject to environmental degradation, and an Extent of Occurrence less than 5000 km² this species must be considered Endangered under Criterion B of the IUCN Red List Categories and Criteria (IUCN 2001),

16. Asclepias graminifolia (Wild) Goyder, comb. nov.

Pachycarpus graminifolius Wild, Kirkia 4: 148 (1964). Type: Zimbabwe, Chimanimani Mts, slopes of Point 71, Goodier & Phipps 199 (holotype SRGH, photo. K).

Trachycalymma graminifolium (Wild) Goyder (2001: 141).

Distribution. Endemic to the Chimanimani Mountains (Wild 1964). Currently it is known only from the Zimbabwean side, but it is likely that populations will also be found in Mozambique.

Specimens Examined. See specimens cited by Goyder (2001: 141) under Trachycalymma graminifolium.

Habitat. Growing in rocky quartzite grassland; 1700 – 2200 m.

Conservation Status. Vulnerable VU D2. Occuring in the protected area of the Chimanimani National Park, this species must nevertheless be considered Vulnerable under Criterion D of the IUCN Red List Categories and Criteria (IUCN 2001) as it is known from just three collections.

17. Asclepias shabaensis (Goyder) Goyder, comb. nov.

Trachycalymma shabaense Goyder, Kew Bull. 56: 144 (2001). Type: Democratic Republic of Congo, Biano Plateau, Katentania, Nov. 1912, Homblé 697 (holotype BR (sheet with single much-branched specimen); isotype BR).

Distribution. Known only from the Katanga region of the Democratic Republic of Congo, formerly known as Shaba.

Specimens Examined. See specimens cited by Goyder (2001: 144) under Trachycalymma shabaense.

Habitat. Black soil on slopes of valley or in open plateau grassland.

Conservation Status. Vulnerable VU B1ab(iii). With an Extent of Occurrence less than 20,000 km² and fewer than ten localities, this species must be considered Vulnerable under Criterion B of the IUCN Red List Categories and Criteria (IUCN 2001).

18. Asclepias buchwaldii (Schltr. & K. Schum.) De Wild. (1904: 185). Type: Tanzania, Usambara, Mombo, Buchwald 375 (B† holotype); T7: Iringa Distr., upper slopes of Image Mountain, Goyder et al. 3924 (neotype K, designated by Goyder (2001: 146); isoneotypes DSM, PRE).

Gomphocarpus buchwaldii Schltr. & K. Schum. (1903: 324).

Asclepias affinis De Wild. (1904: 184), non Gomphocarpus affinis Schltr. (1895a: 27), nec Asclepias affinis (Schltr.) Schltr. (1896: 455). Type: Vieux Kasongo, Aug. 1896, Dewèvre 952 bis (holotype BR).

Asclepias buchwaldii var. angustifolia De Wild. (1904: 185). Type: Vieux Kasongo, Aug. 1896, Dewèvre 952 (holotype BR).

Trachycalymma buchwaldii (Schltr. & K. Schum.) Goyder (2001: 146).

Distribution. Known from the southern highlands of Tanzania and adjacent regions of Malawi and Zambia. Also occurs in northern Tanzania, Burundi and the Democratic Republic of Congo.

Selected Specimens. See specimens cited by Goyder (2001: 148) under Trachycalymma buchwaldii.

Habitat. Growing in grassland or Brachystegia woodland, usually on steep rocky hillsides; 900 – 2400 m.

Conservation Status. Least Concern (LC).

19. Asclepias minutiflora (Goyder) Goyder, comb. nov.

Trachycalymma minutiflorum Goyder, Kew Bull. 56: 148 (2001). Type: Ethiopia, Shoa Province, near Baco, Sept. 1969, Mogk 234 (holotype EA, photo. K).

[Schizoglossum uollegaense Chiov. in schaed. (Benedetto 97 (FT)).]

Distribution. Known only from Shoa, Illulabor and Welega provinces in western Ethiopia.

Specimens Examined. See specimens cited by Goyder (2001: 148) under Trachycalymma minutiflorum.

Habitat. Growing in grassland; 1650 – 1800 m.

Conservation Status. Vulnerable VU B1ab(iii). With an Extent of Occurrence less than 20,000 km² and fewer than ten localities, this species must be considered Vulnerable under Criterion B of the IUCN Red List Categories and Criteria (IUCN 2001).

20. Asclepias ameliae S. Moore (1912: 345). Type: Angola, between Forte Princeza Amelia and the R. Kubango, 1 Nov. 1905, Gossweiler 2199 (holotype BM) — reported in error by Moore (1912: 345) as 2176 (Goyder 2001: 152).

Gomphocarpus pulchellus Decne. (1838: 325). Type: Angola, Benguela Plateau, da Silva s.n. (holotype P; isotype K).

Asclepias pulchella (Decne.) N. E. Br. (1902: 346), non A. pulchella Salisb. (1796: 150).

Trachycalymma pulchellum (Decne.) Bullock (1953b: 350), pro parte.

Distribution. Recorded from Angola, western and central Zambia, and the Katanga province of the Democratic Republic of Congo.

Selected Specimens. See specimens cited by Goyder (2001: 152) under Trachycalymma pulchellum.

Habitat. Open, mixed deciduous woodland, or occasionally in seasonally waterlogged grassland; c. 1200 – 1500 m.

Conservation Status. Least Concern (LC).

21. Asclepias schumanniana Hiern (1898: 686). Type: Angola, Pungo Andongo, Pedra de Cazella, Dec. 1856, Welwitsch 4169 (lectotype K, designated by Goyder (2001: 152); isolectotypes B†, BM, C, P). Paralectotype: Angola, near Malanje, Mechow 400 (B†, K).

Gomphocarpus amoenus K. Schum. (1893: 124), non Asclepias amoena L. (1753: 214), nec. Brongn. (1831: 275), nec Ruiz & Pavon ex Hemsl. (1881: 325). Type as for A. schumanniana Hiern.

A. gossweileri S. Moore (1911: 155). Type: Angola, Camona, Ambaka, Gossweiler 4557 (holotype BM).

Trachycalymma amoenum (K. Schum.) Goyder (2001: 152).

Distribution. Known from Angola, the Democratic Republic of Congo, Rwanda, Burundi and western Tanzania.

Selected Specimens. See specimens cited by Goyder (2001: 153) under Trachycalymma amoenum.

Habitat. In valley grassland or on rocky hillsides; c. 1500 – 1600 m.

Conservation Status. Least Concern (LC).

22. Asclepias foliosa (K. Schum.) Hiern (1898: 686). Type: Democratic Republic of Congo, Mukenge, Pogge 1130 (lectotype K, designated by Goyder (2001: 153); B†). Paralectotypes: Mukenge, Pogge 1191 & 1223 (B†).

Gomphocarpus foliosus K. Schum. (1893: 126).

Asclepias modesta N. E. Br. (1902: 348). Type: Malawi, Namasi, Cameron 6 (lectotype K, designated by Goyder (2001: 153). Paralectotypes: Tanzania, N of Lake Malawi [Nyasa], Thomson s.n. (K); Malawi/Zambia, ‘N Nyasaland and upper Loangwa R.’, 1896 – 1897, Nicholson s.n. (K); Malawi, near Blantyre, Last s.n. (K); Manganja Hills, Waller s.n. (K).

Asclepias modesta var. foliosa N. E. Br. (1902: 349). Type: Angola, Huilla, near Lopollo, Welwitsch 4174 (holotype K; isotype BM).

Asclepias lepida S. Moore (1912: 344). Angola, Kubango, near Forte Colui, 18 Oct. 1905, Gossweiler 2176 (holotype BM).

Asclepias minuta A. Chev. (1917: 272). Type: Benin, Atacora Mts, Kouende, 23 June 1910, Chevalier 24227 (holotype P, photo K).

Trachycalymma pulchellum sensu Bullock (1963: 92).

Trachycalymma foliosum (K. Schum.) Goyder (2001: 153).

Distribution. Recorded from the savanna regions of West Africa, and the Brachystegia belt of southern tropical Africa.

Selected Specimens. See specimens cited by Goyder (2001: 155) under Trachycalymma foliosum.

Habitat. Open, mixed deciduous woodland over most of its range, but frequently occuring in grassland in West Africa; (600 – )1100 – 2000 m.

Conservation Status. Least Concern (LC).

23. Asclepias eminens (Harv.) Schltr. (1896: 453). Type: South Africa, KwaZulu-Natal, Zululand, Gerrard & McKen 1291 (holotype TCD; isotypes BM, K).

Gomphocarpus eminens Harv. (1863: 60, t. 195).

Stenostelma eminens (Harv.) Bullock (1953b: 342).

Distribution. Central Zimbabwe and north-eastern parts of South Africa (NW Province, Mpumalanga, KwaZulu-Natal), and Swaziland and Lesotho.

Selected Specimens. Zimbabwe. C: Harare [Salisbury], between Avondale West and Mabelreign, 23 Oct. 1955, Drummond 4916 (BR, K, SRGH); vlei near Felixburg, 20 Nov. 1971, Cannell 483 (K, SRGH); W: Bulawayo, Jan. 1898, Rand 189 (BM).

Habitat. Seasonally burned, and frequently also seasonally waterlogged grassland; c. 1500 m in Zimbabwe, 600 – 1800 m in South Africa.

Conservation Status. Least Concern (LC).

24. Asclepias nuttii N. E. Br. (1898: 308). Type: Tanzania, ‘between Lake Tanganyika and Lake Rukwa’, Nutt s.n. (holotype K).

Stathmostelma nuttii (N. E. Br.) Bullock (1953a: 55).

Distribution. Known from several localities on the Ufipa Plateau and the area SW of Mbeya, with a single collection from central Malawi. Surprisingly, this species has not been recorded from the adjacent Mbala region of Zambia.

Specimens Examined. Tanzania. T4: Ufipa Distr., 2 km W of Mkowe on road to Chapota, 21 Nov. 1994, Goyder et al. 3772 (DSM, K); 10 km from Mumba on way to Sumbawanga, directly opposite prison camp, 18 Dec. 1986, D. & J. Moyer 62 (K); road to Mpui, 3 Nov. 1956, Richards 6846 [or 6848?] (K); Mpui – Mbala [Abercorn] road, close to border, 7 Nov. 1954, Richards 3544 (K); between Lake Tanganyika and Lake Rukwa, Nutt s.n. (holotype K). T7: Mbeya Distr., Vwawa, 21 Dec. 1971, [collector not recorded] 879 (EA) & 9 Jan. 1976, Leedal 3313 (K); Mbozi, Magambo Mbuga, 21 km from Igamba, 15 Dec. 1978, Leedal 5239 (K); Iringa Distr., Kisolansa Farm, 2 Jan. 1998, de Leyser 318 (K) & 28 Jan. 1999, de Leyser 331 (K). Malawi. C: Chongoni Forest School, base of Chiwao Hill, 4 Feb. 1959, Robson 1445 (K).

Habitat. Seasonally waterlogged ‘dambo’ grassland; 1500 – 1800 m.

Conservation Status. Vulnerable VU B1ab(iii). Although widely distributed in the region, the Extent of Occurrence is less than 20,000 km², and the species is known from fewer than ten localities. The habitat is threatened, being at relatively low altitude in well-populated areas. I have therefore assessed the conservation status as Vulnerable under Criterion B of the IUCN Red List Categories and Criteria (IUCN 2001).

Notes. This species is distinctive with a single terminal inflorescence per branch. The translator arms are differentiated into proximal and distal sections, as in Stathmostelma, but the proximal portion is not so conspicuously expanded. The conspicuous notch in the anther wings suggests a possible link to Asclepias eminens.

25. Asclepias occidentalis Goyder sp. nov. Ab A. eminenti inflorescentiis extra-axillaribus (nec terminalibus) et corona columnam ± aequanti (nec quam columna duplo longiore) differt; a speciebus Stathmostelmae ala antherarum incisura conspicua basin versus ornata, pedunculis brevioribus, floribus minus prominentibus differt. Typus: Democratic Republic of Congo, Kinshasa [Leopoldville], 18 Feb. 1950, Baldwin 14170 (holotypus K; isotypus US).

Perennial herb with one to several annual stems arising from a slender vertical tuber; stems 15 – 30 cm long, simple, erect, minutely but densely pubescent. Leaves sessile, slightly fleshy; lamina 9 – 13 × 0.2 – 0.3 cm, narrowly linear, attenuate both apically and at the base, minutely pubescent with scattered reddish hairs on both surfaces. Inflorescences extra-axillary forming umbels of 3 – 7 erect flowers, peduncles 0.5 – 1 cm long, minutely but densely pubescent; bracts c. 3 mm long, filiform, glabrescent; pedicels 0.7 – 1.4 cm long, pubescent. Sepals 2 – 3 × 1 mm, ovate to broadly triangular, attenuate, glabrous. Corolla reflexed, lobes 5 – 6 × 3 mm, ovate, subacute, adaxial surface green, minutely papillose, abaxial face brown, subglabrous or pubescent. Corona lobes attached ± at the base of the staminal column, 3 mm long, ± as tall as the column, erect, cucullate with a fleshy midline, lateral margins inrolled and meeting centrally along the inner face, the lobes ± cylindrical in lower half, the apex more dilated above. Anther wings c. 2 mm long, margins curved very slightly above the conspicuous basal notch, rounded abruptly towards the column beneath the notch. Corpusculum c. 0.4 × 0.2 mm, ± ovoid, brown; translator arms with a broadly winged proximal portion c. 0.5 × 0.2 mm, the distal portion strongly geniculate, 0.2 mm long, narrow and subcylindrical, then broadening into a clasping overlap with the pollinium; pollinia c. 1.2 × 0.6 mm, flattened, oblong. Stylar head ± level with top of anthers. Follicle single by abortion, erect, c. 22 × 0.5 cm, long-fusiform, the lower 7 cm forming a slender stipe. Seeds not seen. Fig. 4A, B.

Distribution. Known from several localities on the Batéké Plateau that runs from SE Gabon to Brazzaville in the neighbouring Republic of Congo, and from the high ground SE of Kinshasa in the Democratic Republic of Congo.

Specimens Examined. Gabon. Haut Ogooué, Batéké Plateau, 24 Sept. 2007, Walters et al. 1947 (LBV, MO). R. Congo. Batéké Plateau, route du km 45, 18 Nov. 1963, Descoings 11416 (MPU); Batéké Plateau, route des falaises de Douvres, mare de Gamakala, 26 Nov. 1962, Descoings 9812 (MPU); Batéké Plateau, km 40, 18 Nov. 1965, Farron 4727 (MPU); N’Koyi Mabaya, route de Kinkala, Dec. 1954, Koechlin 2336 (MPU); Lousséké, route de Manyanga, 19 Feb. 1950, Koechlin 435 (MPU); Cataractes, Yangui, 35 km de Brazzaville vers Kinkala, 14 Dec. 1962, de Néré 157 (MPU) & vers le village de Bon Espoir, 14 Dec. 1962, de Néré 80 (MPU); Batéké Plateau, Mandielé vers Maloukou, mare N’Gatsou, 22 Feb. 1964, Sita 932 (MPU); 33 km de Brazzaville vers M’Bé, 7 Dec. 1954, Trochain 9222 (MPU); Lisière de Lousséké, M’Bamou – Kinkala, May 1956, Trochain 9516 (MPU). D. R. Congo. III: Kinshasa [Leopoldville], 18 Feb. 1950, Baldwin 14170 (K, US); Kimuenza, 16 Jan. 1957, Robyns 4162 (BR); between Kinshasa and Kasangulu, 27 Dec 1981, Lejoly 81/748 (BRLU (Lachenaud pers. comm.), not seen). IV: Panzi, 6 Feb. 1952, Callens 3102 (K).

Habitat. Recently burned savannah grasslands. 500 – 600 m.

Conservation Status. Near Threatened (NT). The localities are spread over a distance of some 600 km north to south, and so probably exceed the Extent of Occurrence of 20,000 km² required for a Vulnerable rating under Criterion B1 of the IUCN Red List Categories and Criteria (IUCN 2001). Nevertheless, the savannah is at relatively low altitude compared to montane grassland in eastern Africa, and is retreating as the forest expands, at least in Gabon. It may also be threatened by cultivation in parts of the range. So I propose a provisional conservation assessment of Near Threatened.

Notes. Asclepias occidentalis has some affinities with Stathmostelma. Vegetatively they are very similar, and some floral characters also support this relationship — the translator arms are winged, but to a lesser extent than Stathmostelma. They are also geniculate, but the distal portion is not strongly developed. The erect narrowly fusiform follicle is similar to that in Stathmostelma.

Asclepias occidentalis shares the conspicuous notch on the anther wings with the A. eminens group, but the inflorescences are extra-axillary not terminal, and the corona lobes are ± as tall as the column rather than twice its length.

26. Asclepias inaequalis Goyder sp. nov. Speciebus Margarettae atque Stathmostelmae similis sed corona reducta non petaloidea et alis antherarum aliter contortis differt. Typus: Tanzania T7, Njombe Distr., edge of Kitulo Plateau near Matamba, 2 Dec. 1994, Goyder, Griffiths, Harvey, Kayombo, Mbago & Paton 3888 (holotypus K; isotypi DSM, EA, PRE, WAG).

Perennial herb with one to several annual stems arising from a slender vertical tuber, the tuber in some cases (Goyder et al. 3888) as long as 30 cm; stems 0.2 – 0.5 m long, simple or little-branched, erect, reddish purple, minutely pubescent with indumentum of white hairs. Leaves subsessile; lamina 3 – 10 × (0.1) 0.3 – 0.7 cm, linear, mostly attenuate apically, attenuate or rounded at the base, margins somewhat revolute, minutely pubescent with stiff white hairs on both upper and lower surfaces. Inflorescences extra-axillary forming umbels of 3 – 6 spreading or erect flowers, peduncles 1 – 5 cm long, reddish with a dense indumentum of white hairs; bracts filiform, densely pubescent, deciduous; pedicels 0.6 – 1.2 cm long, pubescent. Sepals 3 – 4 mm long, linear to narrowly triangular, attenuate, generally reddish with white hairs. Corolla ± rotate to weakly reflexed, lobes 4 – 6 × 2 – 3 mm, ovate, subacute, adaxial surface pale green or cream, glabrous or minutely papillose, abaxial face reddish purple, pubescent. Corona lobes attached ± at the base of the staminal column, 3 – 4 × 2.5 – 3 mm, broadly obovate, erect, taller than the column and with the tip arching over it, dorsoventrally compressed but somewhat fleshy with a thickened midline and a pair of thin flanges running along the midline on the inner face, and two further fleshy ridges lying horizontally near the base of the inner face, lobes cream or green, frequently suffused with brown or purple along the midline and the apex. Anther wings 1 mm long, margins ± parallel to the column but curved and distorted in their lower halves. Corpusculum c. 0.3 × 0.1 mm, subcylindrical, brown; translator arms c. 0.5 mm long, flattened and c. 0.1 mm broad, very weakly geniculate; pollinia c. 0.7 × 0.25 mm, flattened, oblong. Stylar head ± level with top of anthers. Mature follicles and seed not seen, but very immature follicle on Goyder et al. 3895 densely pubescent and held erect on apparently elongating peduncle. Fig. 5.

Fig. 5

Asclepias inaequalis. A habit; B rootstock; C young follicle; D flower; E adaxial face of corona lobe; F pollinarium; G anther, with contorted margins. A & B from Goyder et al. 3888; C & G from Goyder et al. 3895; D – F from Richards 18489. drawn by margaret tebbs.

Distribution. Restricted to Mbeya Peak, the Kitulo Plateau, Mt Rungwe and the Poroto and Kipengere ranges in the Southern Highlands of Tanzania.

Specimens Examined. Tanzania. T7: Njombe Distr., edge of Kitulo Plateau near Matamba, 2 Dec. 1994, Goyder et al. 3888 (holotype K; isotypes DSM, EA, PRE, WAG); top of Kitulo Plateau, 4 Dec. 1994, Goyder et al. 3895 (BR, C, DSM, EA, PRE, WAG); Kitulo Plateau 2 miles E of Kikondo, 21 Nov. 1977, Leedal 4717 (K); Kikondo, 25 Nov. 1979, Leedal 5797 (K); Kikondo, 20 Oct. 1956, Richards 6667 (K); Kitulo Plateau above Matamba, near waterfall on headwaters of Ndumbi R., 22 Nov. 1986, Brummitt & Mwasumbi 18102 (K); above Ndumbi R., 30 Nov. 1963, Richards 18489 (K); slopes of Matamba Mt, 22 Nov. 1986, Goldblatt et al. 8215 (K, MO); Kitulo [Elton] Plateau, 12 Nov. 1931, Davies E27 (K); Kitulo [Elton] Plateau, 29 Nov. 1963, Richards 18451 (K); Kipengere Mts, 10 Jan. 1957, Richards 7652 (K); Poroto Mts, Ifupa, 21 Dec. 1978, Leedal 5249 (K); Mt Rungwe, W ridge above Lwangwa, Leedal 5207 (K); N slopes of Mt Rungwe, 9 Nov. 1966, Gillett 17671 (EA); Rungwe Mt, fishing camp, Kiwira R., 9 Dec. 1963, Richards 18611B (K); Mbeya Peak, 25 Nov. 1961, Kerfoot 3249 (EA).

Habitat. Montane, seasonally burned grassland but occasionally in more disturbed areas. Mostly in peaty soils; 2200 – 2900 m.

Conservation Status. Least Concern (LC). Although restricted to the central part of the Mbeya Highlands, this species occurs frequently, and appears to withstand, or even to prefer, disturbed ground.

Phenology. Flowering with the early rains (October – January).

Notes. The asymmetrically distorted base to the anther wings in the new species, where the anther wings of adjacent anthers are differentially contorted, appears to be unique among African Asclepias. Goyder (2003) reported another case of this anther morphology from the distantly related South American species Morrenia stuckertiana (Kurtz ex H. Heger) Malme (Asclepiadeae: subtribe Oxypetalinae).

Asclepias inaequalis appeared in a well-supported clade with species of Stathmostelma and Margaretta in the molecular study of the subtribe Asclepiadeae (Goyder et al. 2007), where it was labelled ‘gen. indet. aff. Asclepias’. Sampling, however, was not sufficient for reliable generic limits to be established in the Asclepias complex, so I have refrained from expanding the concept of Margaretta to include Stathmostelma and this species until a better sampled and more fully resolved picture becomes available, and characters have been identified that can be used to recognise this lineage morphologically. The pollinarium of A. inaeqalis has flattened translator arms, longer than in Margaretta rosea, but otherwise consistent with such a relationship. The corona could be interpreted as a reduced version of M. rosea with a thickened mid-line and the lateral teeth reduced to fleshy pegs. However, the corona is also similar to that of Pachycarpus pachyglossum, endemic to the Ufipa highlands, whose habit and leaf morphology suggested placement in Pachycarpus when described by Goyder (1998a).

27. Asclepias breviantherae Goyder sp. nov. Ab A. mtorwiensi foliis pubescentibus, corolla abaxialiter pubescenti, alis antherarum in lineis connatis 0.2 mm longis tantum dispositis atque infra capitulo gynostegii divergentibus curvatisque (nec per totam longitudinem (0.4 mm) in lineis connatis dispositis) differt. Typus: Tanzania T7, Rungwe Distr., Poroto Mts E of Kikondo on road to Kitulo, 1 Dec. 1994, Goyder, Griffiths, Harvey, Mbago & Paton 3872 (holotypus K; isotypi DSM, EA, PRE, WAG).

Perennial herb with one to several annual stems arising from a napiform tuber; stems 6 – 12 (– 25) cm long, simple or little-branched, prostrate to erect, reddish, minutely pubescent with indumentum of white hairs. Leaves subsessile; lamina 3 – 7 × 0.2 – 1 cm, linear to narrowly lanceolate or oblong, mostly attenuate apically, and narrowing abruptly at the base, margins not revolute, minutely pubescent with stiff white hairs on both upper and lower surfaces, or indumentum restricted to principal veins. Inflorescences extra-axillary forming umbels of 2 – 7 spreading or erect flowers; peduncles 0.5 – 4 cm long, reddish with a dense indumentum of white or rusty hairs; bracts filiform, pubescent; pedicels 0.3 – 1 cm long, pubescent. Sepals (2 –) 2.5 – 3 × 0.7 – 1 mm, narrowly oblong to lanceolate, attenuate, generally reddish with white hairs. Corolla campanulate, lobes (3 –) 5 – 6 × 2 – 2.5 mm, oblong to narrowly ovate, subacute, adaxial surface pale green or cream with pinkish tinge, glabrous or minutely papillose, abaxial face reddish purple, pubescent. Gynostegium with stipe 0.7 – 1.5 mm long. Corona lobes attached to and obscuring the gynostegial stipe, c. 1.5 mm tall, spreading from the column then curved upwards, somewhat pouched with a thickened fleshy midline and two short rounded auricles apically, cream tinged with red. Anther wings 1 mm long but parallel grooved portion (guide rails) only 0.2 mm long, the remainder flared and curved below the head of the gynostegium. Corpusculum c. 0.25 × 0.1 mm, ovoid-subcylindrical, brown; translator arms c. 0.4 mm long, flattened but very slender (c. 0.05 mm) and strongly geniculate, with distinct proximal and distal sections; pollinia 0.3 – 0.4 × 0.3 mm, somewhat flattened, triangular in outline. Stylar head flat or domed. Follicles (Leedal 5301; Pawek 9330) held erect on elongated peduncle, to c. 9 cm long, slender, fusiform, minutely pubescent. Seeds c. 3 × 2 mm, ovoid in outline, with one plane face and one strongly convex, sparsely verrucose and with a narrow marginal rim; coma c. 1.5 cm long.

Key to Subspecies

• Corolla lobes at least 5 mm long; gynostegium raised on stipe 1 – 1.5 mm long; stylar head domed

• . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . subsp. breviantherae

• Corolla lobes c. 3 mm long; gynostestegial stipe c. 0.7 mm long; stylar head ± flat . . . . . . . . . . . . . . . subsp. minor

• subsp. breviantherae

Sepals 2.5 – 3 mm long. Corolla lobes 5 – 6 × 2 – 2.5 mm, oblong to narrowly ovate. Gynostegium with stipe c. 1 – 1.5 mm long, raising the anthers above the level of the corona. Stylar head domed, extending c. 1 mm beyond top of anthers but obscured beneath the conspicuous, membranous anther appendages. Fig. 6A, B.

Fig. 6

Asclepias breviantherae A, B subsp. breviantherae. A habit; B flower. C, D subsp. minor. C habit; D flower. A from Goyder et al. 3872; B from Richards 6689; C from Richards 7685; D from Richards 18510. drawn by margaret tebbs.

Distribution. Restricted to the Southern Highlands of Tanzania (Kitulo, Poroto and Mbeya massifs) and the nearby Nyika Plateau of northern Malawi.

Specimens Examined. Tanzania. T7: Rungwe Distr., Poroto Mts E of Kikondo on road to Kitulo, 1 Dec. 1994, Goyder et al. 3872 (holotype K; isotypes DSM, EA, PRE, WAG); Kikondo, 21 Oct. 1956, Richards 6689 (K); Poroto Mts, Mwela, 22 Jan. 1979 (in fruit), Leedal 5301 (K); Poroto ridge road, 11 Nov. 1966, Gillett 17742 (EA); Kitulo [Elton] Plateau, 24 Jan. 1961, Richards 14153A (K) & 29 Nov. 1963, Richards 18452 (K); Mwapamansa Mt, on road from Igoma to Kitulo, 15 Oct. 1977, Leedal 4634 (K); top of pass from Matamba to Kitulo, 21 Nov. 1977, Leedal 4729 (K); slopes of Matamba Mts, 22 Nov. 1986, Goldblatt et al. 8195 (E, MO); summit of Mbeya Peak, 11 Feb. 1978, Leedal 4916 (K); Mbeya Peak, 28 Nov. 1961, Kerfoot 3140 (EA). Malawi. N: Rumphi Distr., Nyika Plateau, Kasaramba Vitumbi junction, 4 March 1977, Pawek 12446 (K, MO); Kasaramba view, 17 April 1975 (in fruit), Pawek 9330 (K); Nyika Plateau, Blue Heather Hill, 12 Dec. 1975, Phillips 564 (K, MO).

Habitat. Thin peaty soil over rock in seasonally burned montane grassland; (2100 –) 2400 – 2800 m.

Conservation Status. Least Concern (LC). Despite its restricted distribution, this taxon occurs in rocky habitats less prone to disturbance from cultivation than surrounding areas, and does not, therefore, appear to be particularly threatened.

Notes. The reduced fleshy corona is reminiscent of that shown by Asclepias minor. The translator arms are very slender and articulated, perhaps indicating a transitional relationship to Stathmostelma. The stipitate gynostegium has very short guide rails between adjacent anthers, the anther wings then curving beneath the stylar head. Characters to distinguish this species from A. mtorwiensis are listed under that species.

Asclepias breviantherae subsp. minor Goyder subsp. nov. A subspeciei typica lobis corollae brevioribus ± 3 mm tantum longis (nec ut minimum 5 mm longis), stipite gynostegii breviore 0.7 mm tantum (nec 1 – 1.5 mm) longi, capitulo styli plano (nec tholiformi) differt. Typus: Tanzania T7, Njombe Distr., Kitulo [Elton] Plateau, Ndumbe R., 11 Jan. 1957, Richards 7685 (holotypus K).

Sepals c. 2 mm long. Corolla lobes c. 3 mm long, ovate. Gynostegial stipe c. 0.7 mm long, the corona therefore reaching the top of the staminal column. Stylar head ± flat, not protruding from the top of the staminal column. Fig. 6C, D.

Distribution. Known from just three collections from the Kitulo Plateau in southern Tanzania.

Specimens Examined. Tanzania. T7: Njombe Distr., Kitulo [Elton] Plateau, Ndumbe R., 11 Jan. 1957, Richards 7685 (holotype K); Mbeya Distr., Kitulo [Elton] Plateau, 24 Jan. 1961, Richards 14153B (K) & 1 Dec. 1963, Richards 18510 (K).

Habitat. Montane grassland; 2100 – 2400 m.

Conservation Status. Endangered EN B2ab(iii). Known from just three almost certainly degraded localities, this subspecies must be considered Endangered under Criterion B of the IUCN Red List Categories and Criteria (IUCN 2001).

Notes. These three collections from the Kitulo Plateau, two from the Mbeya side and one from the Njombe side have a very different facies to collections of the type subspecies. However, the principal differences amount essentially to smaller flowers with a shorter gynostegial stipe and a less domed stylar head. As the corona is unchanged, this gives the flower a very different appearance, as the gynostegium is largely obscured by the corona lobes.

These collections are reported from slightly lower altitude than most records of subsp. breviantherae, and the specific habitat (shallow soil over rock) of that subspecies is not mentioned. However, Mary Richards’ labels, if they are to be believed, imply that on one occasion she collected both subspecies together (Richards 14153A & B), at an altitude of c. 2100 m. It is always possible that this was not the case and that the larger flowered plants (Richards 14153A) were collected at a higher elevation than the small-flowered ones (Richards 14153B), perhaps supplementing collections made earlier in the day, in the belief that this was the same taxon.

Given the somewhat superficial nature of the floral variation, and the suggestion of altitudinal separation, it seems most appropriate to recognise these taxa at the rank of subspecies.

28. Asclepias mtorwiensis Goyder sp. nov. Ab A. breviantherae foliis glabris, corolla abaxialiter glabra, partibus parallelis alarum antherarum multo longioribus, 0.4 mm (nec 0.2 mm tantum) longis differt. Typus: Tanzania, Makete Distr., Kipengere Mts, slopes of Mtorwi Mt above Ndumbi Forest Reserve, 23 Nov. 1986, Brummitt, Congdon & Mwasumbi 18142 (holotypus K).

Perennial herb with a single annual stem arising from a tuberous rootstock (not seen); stems 8 – 12 cm long, simple, erect, reddish, minutely pubescent with indumentum of white hairs. Leaves subsessile, semi-succulent; lamina 5 – 10 × 0.2 – 0.3 cm, narrowly linear, attenuate both apically and basally, margins revolute, glabrous. Inflorescences extra-axillary forming umbels of 5 – 9 spreading or erect flowers; peduncles 0.5 – 1 cm long, reddish, minutely pubescent; bracts filiform, pubescent; pedicels 0.5 – 0.7 cm long, pubescent. Sepals c. 1.5 mm long, narrowly triangular, glabrous. Corolla campanulate or spreading, perhaps even weakly reflexed, lobes c. 3 × 2 mm, ovate-oblong, subacute, adaxial surface cream with reddish tinge, glabrous, abaxial face reddish green, glabrous. Corona lobes arising from the base of the staminal column, c. 1.5 mm tall and reaching ± the top of the column, pouched and somewhat fleshy, with three short rounded teeth apically, and two rounded lobes on the lateral margins, cream. Anther wings 0.4 mm long. Corpusculum c. 0.25 × 0.1 mm, ovoid-subcylindrical, brown; translator arms c. 0.2 mm long, very slender, not geniculate; pollinia c. 0.3 × 0.2 mm, somewhat flattened, oblong-elliptic. Stylar head ± flat. Follicles and seeds not seen. Fig. 4C, D.

Distribution . Known only from the type, which appears to be a unicate.

Specimens Examined. Tanzania. T7: Makete Distr., Kipengere Mts, slopes of Mtorwi Mt above Ndumbi Forest Reserve, 23 Nov. 1986, Brummitt et al. 18142 (holotype K).

Habitat. Open rocky hillside; c. 2700 m.

Conservation Status. Critically Endangerered CR B2ab(iii). Known only from one locality at the highest point of the Kitulo/Kipengere range, this species must be considered Critically Endangered by any warming of the climate.

Notes. Vegetatively this species appears close to Asclepias minor. The pouched, fleshy corona is similar to that of A. breviantherae, but could also be interpreted as a reduced form of A. amabilis. Other differences from A. breviantherae include the glabrous leaves and corolla, the gynostegium which is less stipitate, the different form of the anther wings, which are 0.4 mm long and form guide rails for their entire length, rather than for only 0.2 mm as in A. breviantherae where they then become flared and curved beneath the head of the gynostegium. The translator arms are filiform and not conspicuously geniculate.

29. Asclepias minor (S. Moore) Goyder comb. nov.

Odontostelma welwitschii Rendle, J. Bot. 32: 161, t. 344 (1894), non Asclepias welwitschii (Britten & Rendle) N. E. Br. (1902: 341). Type: Angola, Huilla, near Lopollo, Welwitsch 4172 (holotype BM; isotypes K, LISC).

Schizoglossum welwitschii (Rendle) N. E. Br. (1902: 365).

Odontostelma minus S. Moore (1912: 363). Type: Angola, between Forte Princesa Amélia and Rio Cubango, Gossweiler 2332 (holotype BM), synon. nov.

Distribution. Known from Angola, Zambia and Zimbabwe.

Specimens Examined. Angola. Huilla, near Lopollo, Welwitsch 4172 (holotype BM; isotypes K, LISC). Zambia. C: Kabwe Distr., Karubwe Protected Forest Area, 34 km N of Lusaka, 7 Oct. 1972, Kornas 2344 (K); Kabwe [Broken Hill], 3 Oct. 1963, Fanshawe 8003 (K); S: Muckle Neuk, 20 km N of Choma, 28 Nov. 1954, Robinson 994 (K). Zimbabwe. C: Harare [Salisbury] Distr., near Makabusi R., 13 Oct. 1972, Grosvenor 772A (K); Cleveland Dam, 9 Oct. 1951, Wild 3664 (K); near Harare [Salisbury], Dec. 1927, King s.n. in Eyles 5229 (K).

Habitat. Flowering in October and November in seasonally waterlogged grassland; 1200 – 1500 m.

Conservation Status. Least Concern (LC).

30. Asclepias alpestris (K. Schum.) Goyder comb. nov.

Schizoglossum alpestre K. Schum., Bot. Jahrb. Syst. 30: 384 (1901). Type: Tanzania, Yawuanga Mt, Kinga range, 13 Sept. 1899, Goetze 1234 (lectotype K, designated here; isolectotypes B†, BR, E).

Distribution. Restricted to the upper reaches of the Kitulo Plateau and Kipengere mountains in the Southern Highlands of Tanzania.

Specimens Examined. Tanzania. T7: top of Kitulo Plateau S of Matamba, 2 Dec. 1994, Goyder et al. 3892 (DSM, K, PRE) & 24 Feb. 1974, Leedal 2230 (K); slopes of Matamba Mt, 22 Nov. 1986, Goldblatt et al. 8197 (K); Kitulo Plateau, crystalline ridges, 12 Dec. 1989, Lovett et al. 3673 (K); Kitulo [Elton] Plateau, Sept. 1959, Procter 1418 (EA) & Oct. 1963, Procter 2437 (EA) & 29 Nov. 1963, Richards 18453 (K) & 26 Aug. 1968, Prins 250 (EA) & 24 Sept. 1968, B. J. & S. Harris 2285 (EA); Yawuanga Mt, Kinga range, 13 Sept. 1899, Goetze 1234 (lectotype K; isolectotypes B†, BR, E).

Habitat. Montane grassland on shallow soil around rocky outcrops; 2600 – 2900 m.

Conservation Status. Vulnerable VU D2. Although the specific habitat of this species does not appear prone to disturbance, the small number of locations lead to an assessment of Vulnerable under Criterion D of the IUCN Red List Categories and Criteria (IUCN 2001).

Notes. Kupicha (1984: 669) excluded this species from the Schizoglossum complex despite the well-developed ligule on the inner face of the corona lobe — normally a good indicator for Schizoglossum. The pollinia, however, lack a transparent germination zone, which would be expected in that genus. Vegetatively and in other floral characters, this species appears closely allied to the Asclepias minor/breviantherae group.

31. Asclepias randii S. Moore (1902: 255). Type: Zimbabwe, Harare [Salisbury], Dec., Rand 194 (holotype BM; isotypes K (fragment and drawing), SRGH). Fig. 7A – C.

Fig. 7

A – C Asclepias randii. A habit; B flower; C corona lobe. D – G A. grandirandii. D habit; E flower; F pollinarium; G corona lobe. A – C from Goyder et al. 3854; D – G from Robson 373. drawn by margaret tebbs.

Distribution. Ranging from the southern highlands of Tanzania and the Nyika Plateau in northern Malawi where it is found in grasslands above c. 1800 m, to S and W Democratic Republic of Congo, Angola, northern Namibia, Zambia and Zimbabwe where it occurs at lower altitude.

Specimens Examined. D. R. Congo. IV: Kasai, 1925, Achten 749A & B (BR); XI: Manika Plateau, 8 Aug. 1913, Robyns 3965 (BR) & 16 Oct. 1987, Schaijes 3732A (BR); Parc National de l’Upemba, Kibara Mts, 18 Sept. 1948, Robyns 3611a (BR); Parc National de l’Upemba, source of R. Kalumengongo, 22 Aug. 1949, de Witte 7491 (BR). Tanzania. T7: Mbeya Distr., Mbeya Peak, 15 km from turn-off, 29 Nov. 1994, Goyder et al. 3854 (DSM, K, PRE); Njombe Distr., Njombe-Igawa road, 4 Feb. 1961, Richards 14224 (EA, K); ridge of white rock on Mlangali-Njombe road, 6 Nov. 1978, Archbold 2665 (K); Ubena, Bulonga, 16 Nov. 1976, Leedal 4012 (K); Ludewa Distr., Livingstone Mts, on ridge 1.5 km S of Msalaba mt, 23 Nov. 1992, Gereau et al. 5139 (K, MO); Iringa Distr., Sao Hill, 17 Dec. 1961, Richards 15714; Mufindi, Ngowasi [Ngwazi] – Sawala road, 11 Nov. 1971, Paget-Wilkes 1009 (EA); Udzungwa Mts, Nyumbanitu [Nyumbenito] Mt, Dec. 1981, Rodgers & Hall 1881 (K). Angola. Chipia, 15 Feb. 1960, Stopp BO 67 (K); Moxico Distr., S of Lusavo Falls, 13 Jan. 1937, Milne-Redhead 4119 (K). Namibia. Otavi Mts, 1993 – 4, Bruyns 5487 (K). Zambia . N: Mwinilunga Distr., dambo 18 km ENE of Kalene Hill, 16 Dec. 1963, Robinson 6088 (EA, K); Dobeka Plain, near Dobeka Bridge, 14 Dec. 1937, Milne-Redhead 3665 (K); Mbala [Abercorn] Distr., top of Kambole escarpment, 1 Feb. 1959, Richards 10829 (K) & 21 Jan. 1955, Richards 3876 (K); Isoka Distr., crest of Mafinga [Mafingis] range, 8 km W of Chisenga Rest House, 22 Nov. 1952, Angus 837 (K). Malawi. N: Rumphi Distr., Nyika Plateau, Chelinda Bridge, 18 Oct. 1975, Pawek 10276 (EA, K); Chelinda Bridge, 29 Aug. 1987, LaCroix 4739 (MO); top of ridge off road to Chelinda, 15 Nov. 1967, Richards 22553 (K); Fingira Rock junction, 5 Nov. 1977, Pawek 13167A (K); Lake Kaulime, 19 Oct. 1975, Pawek 10304 (K); Nyika Plateau, 8 km E of road to Rest House, 23 Oct. 1958, Robson & Angus 300 (K); Chitipa Distr., Nyika National Park, Nganda Peak 15 km NNE of Chelinda, fruiting 23 Jan. 1992, Goyder et al. 3557a (K). Zimbabwe. C: Harare [Salisbury], Dec., Rand 194 (holotype BM; isotypes K, SRGH); S Marondera [Marandellas], Nov. 1931, Myres 127A (K); C/S: Enkeldoorn – Gutu road, 8 km S of Sebakwe R., 4 Dec. 1960, Leach & Chase 10538 (K); E: Mutare Distr., Mutare [Umtali] Golf Course near Range Hill, 22 March 1960, Chase 7407B (K).

Habitat. Montane grassland and seasonally waterlogged ‘dambo’ grasslands; (1000 –) 1500 – 2800 m.

Conservation Status. Least Concern (LC).

Notes. Two Zambian collections (Richards 15383 from Kawambwa and Milne-Redhead 3175 from Mwinilunga) are anomalous in lacking indumentum on the leaves and corolla.

32. Asclepias grandirandii Goyder sp. nov. Ab A. randii follis oblongis vel ellipticis (nec anguste linearibus), base folii rotundata vel truncata vel leniter cordata (numquam attenuata) differt. Typus: Malawi N: near Chelinda CDC Camp, 26 Oct. 1958, Robson 373 (holotypus K).

Perennial herb with one to many annual stems arising from a vertical napiform tuber; stems 10 – 30 cm long, simple or branched below, prostrate to ascending or erect, green, conspicuously pubescent with spreading white hairs. Leaves subsessile; lamina 3 – 5 × 0.5 – 2 cm, oblong, triangular-oblong or elliptic, apex acute, base rounded, truncate or weakly cordate, with sparse indumentum of spreading white hairs especially on the margins and midrib. Inflorescences extra-axillary forming umbels of 3 – 5 erect flowers; peduncles 1 – 3 cm long, densely pubescent; bracts filiform, pubescent; pedicels 1 – 2 cm long, densely pubescent. Sepals 3 – 6 × 0.5 – 2 mm, linear, lanceolate or narrowly triangular, acute, densely spreading-pubescent. Corolla partially reflexed, lobes 5 – 8 × 3 – 4 mm, oblong to broadly ovate, acute, adaxial surface greenish white, glabrous, abaxial face green tinged brown or purple, spreading-pubescent with white hairs. Corona lobes arising at the base of the staminal column, 5 – 7 mm long, ± cucullate basally with upper margins reaching top of column, the mid-line drawn out into a long-attenuate tip, acute or rounded apically, off-white with a reddish fleshy midline, or the entire lobe mottled red, cavity and mid-line of lobe papillose. Anther wings (1.4 –) 1.5 – 2 mm long. Corpusculum 0.35 – 0.4 × 0.1 mm, subcylindrical, brown, with narrow translucent flanges down the sides; translator arms c. 0.5 mm long, geniculate and broadening distally to form a clasping overlap with the pollinia; pollinia c. 0.9 × 0.5 mm, somewhat flattened, obtriangular. Stylar head ± flat. Follicles (immature) 6 cm long, erect, fusiform, densely pubescent; seeds not seen. Fig. 7D – G.

Distribution. Known from the Mitumba range running between Kolwezi and Kalemia in SE Democratic Republic of Congo, the Ufipa Plateau in SW Tanzania, the Mbala and Kasama districts of NE Zambia, and the Nyika and Vipya Plateaus of northern Malawi.

Specimens Examined. D. R. Congo. XI: near Kolwezi, 14 Oct. 1984, Schaijes 2414 (BR); Manika Plateau, Biano – Lualaba, Nov. 1912, Homblé 791 (BR); Biano Plateau, Greleo, Oct. 1939, Quarré 6006b (BR); Parc National de l’Upemba, Kibara Mts, 18 Sept. 1948, Robyns 3611b (BR) & escarpment near source of R. Kadidika, Aug. 1949, de Witte 7609 (BR) & R. Lusinga, 21 Oct. 1948, de Witte 4560b (BR); Kapona – Kalemie [Albertville] road, 22 July 1957, Devred 3732 (BR). Tanzania. T4: Ufipa Distr., Chapota, 4 Dec. 1949, Bullock 2033 (K). Zambia. N: Mbala [Abercorn] Distr., top of Chilongowelo escarpment, 27 Dec. 1956, Richards 7360 (K) & 5 Feb. 1955, Richards 4339 (K) & 22 Dec. 1954, Richards 3726 (K); above Chilongowelo Farm, Pemba, 15 Dec. 1951, Richards 57 (K); path from Lunzua road to Chisungu escarpment, 26 Jan. 1962, Richards 15957 (K); 80 km E of Luwingu, 30 Dec. 1958, Robinson 2961 (K). Malawi. N: Nyika Plateau, Kasaramba road, 17 Nov. 1967, Richards 22589 (K); near Chelinda CDC Camp, 26 Oct. 1958, Robson 373 (holotype K); Chelinda Bridge, 5 Nov. 1977, Pawek 13183B (K); Mzimba Distr., Chimpyai View, Vipya, 60 km SW of Mzuzu, 23 Dec. 1970, Pawek 4139 (K) & 22 Nov. 1975, Pawek 10358 (K); Nkhata Bay Distr., Vipya Plateau, 15 km SE on Vipya Link road, then S on Kawandama road, 12 Nov. 1977, Pawek 13240 (K); 4 km SE of Chikangawa, 4 Nov. 1978, Phillips 4171B (K); 20 km S of Chikangawa, 27 Oct. 1978, Phillips 4138 (K); Vipya Plateau, 1948, Benson 1536 (BM).

Habitat. In seasonally burned upland grassland or woodland; 1400 – 2200 m.

Conservation Status. Least Concern (LC).

Notes. This is essentially a broad-leaved version of Asclepias randii with longer pedicels and slightly larger It is at least partially sympatric with A. randii, and although the differences seem slight, the overall appearance of the plant is very different — the leaves tend to be shorter and broader in this species than in A. randii, and the leaf base is rounded to truncate or weakly cordate, but never attenuate as in the latter species. The geographic range of this species is somewhat narrower than A. randii. Pubescence is conspicuous, but the 1 mm long hairs of A. randii were not observed.

33. Asclepias aurea (Schltr.) Schltr. (1896: 455). Type: South Africa, Mpumalanga, near Barberton, 1889, Galpin 580 (holotype B†; isotypes GRA, K, PRE).

Schizoglossum pedunculatum Schltr. (1893: 50), non Asclepias pedunculata (Decne.) Dandy (1952: 401). Type: South Africa, between Kenilworth and Claremont near Cape Town, Feb. 1892, Schlechter 351 (holotype B†; isotype BOL).

Gomphocarpus aureus Schltr. (1894: 17).

Gomphocarpus schizoglossoides Schltr. (1894: 21). Type: South Africa, Mpumalanga, Saddleback Mt near Barberton, Galpin 500 (holotype B†; isotypes K, PRE, SAM).

Asclepias aurea var. brevicuspis S. Moore (1902: 255). Type: Zimbabwe, Harare [Salisbury], Sept. 1898, Rand 638 (holotype BM).

Asclepias aurea var. vittata N. E. Br. (1908: 686). Type: South Africa, Mpumalanga, Saddleback Mt near Barberton, Galpin 500 (lectotype K, designated here; isolectotypes PRE, SAM). Paralectotypes: Lesotho [Basutoland], Cooper 932 (K); South Africa, Free State, Bethlehem, Richardson s.n. (K); KwaZulu-Natal, Biggarsberg, Wood 4555 (K, NH); near Newcastle, Wood 5892 (BM); Swaziland, between Carolina and Mbabane (Embabaan), Bolus 12152 (K, BOL); Mbabane [Embabaan], Miller s.n. (K, PRE).

Asclepias radiata S. Moore (1912: 345). Type: Angola, Kubango R. near Forte Princeza Amelia, Gossweiler ‘with 4210’ (holotype BM), synon. nov.

Aidomene parvula Stopp (1967: 21). Type: Angola, Distr. Nova Lisboa, Canjangu, 2 Nov. 1959, Stopp BO 129 (holotype K, not traced; isotypes LISC, M).

Distribution. Angola, Zambia, the Katanga plateaus of south-eastern Democratic Republic of Congo, Zimbabwe, northern South Africa (NW Province, Limpopo, Mpumalanga and KwaZulu-Natal), Swaziland and Lesotho.

Selected Specimens. Angola. Distr. Nova Lisboa, Canjangu, 2 Nov. 1959, Stopp BO 129 (LISC, M). Zambia. W: Mwinilunga Distr., 16 km along road from Matonchi Farm, 17 Nov. 1962, Richards 17269 (K); N: Mporokoso Distr., Kalungwishi headwaters, 11 Jan. 2000, Bingham & Beel 12113 (K); Luwingu Distr., Chishinga Ranch, 4 Dec. 1961, Astle 1052 (K). D. R. Congo. XI: Kundelungu Plateau, 6.5 km NNW of Katshupa post, 19 Oct. 1966, Malaisse 4696 (BR, K). Zimbabwe. W: Matobo Distr., Besna Kobila farm, Sept. 1956, Miller 3667 (K); C: Makoni Distr., 1 mile from Eagles Nest towards Rusape, 29 Nov. 1955, Drummond 5070 (K, SRGH); E: Chimanimani Mts, E side of Bundu plain, 31 Dec. 1957, Goodier & Phipps 242 (K, SRGH).

Habitat. Periodically burned montane or seasonally waterlogged grassland; 1000 – 2000 m.

Conservation Status. Least Concern (LC).

Notes. This species appears most closely allied to Asclepias randii, but is much more slender, possessing long slender peduncles, particularly from the lower nodes. The flowers are variable in colour, perhaps deserving infraspecific taxonomic recognition — most South African material has yellow coronas, but some are cream. Zambian, Katangan and possibly Angolan collections have a white corona.

A handwritten note by N. E. Brown in the Kew Library’s copy of Verh. Bot. Vereins Prov. Brandenburg 35: 50 (1893), states that he has dissected the corona of Schlechter 351 (the type of Schizoglossum pedunculatum), that it is identical to that of Asclepias aurea, and that the description in Schlechter’s diagnosis is incorrect.

Material from Angola described as Asclepias radiata S. Moore appears to belong to this species, but differs in the more hispid indumentum of the stem and leaves. However, Zambian material is more pubescent than most material from further south, so it may be best to regard it just as a local form.

34. Asclepias cucullata (Schltr.) Schltr. (1896: 455). Type: South Africa, Mpumalanga, Saddleback Mt, Barberton, 21 Sept. 1890, Galpin 1034 (isotype K).

Gomphocarpus cucullatus Schltr. (1894: 17).

Trachycalymma cucullatum (Schltr.) Bullock (1956: 620).

Key to Subspecies:

• Corona lobes with papillae restricted to narrow band across base of lobe . . . . . . . . . . . . . . . . . . . . . subsp. cucullata

• Corona lobes with papillae distributed over most of the cavity of the lobe; Chimanimani and Vumba . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . subsp. scabrifolia

• subsp. cucullata

Distribution. Known from the Great Dyke and Nyanga highlands of Zimbabwe, the Zoutpansberg in South Africa, then following the mountain chain from Pilgrims Rest and the Barberton Mts through Swaziland and KwaZulu-Natal to the Transkei.

Selected Specimens. See specimens cited by Goyder (2001: 159).

Habitat. Open grassland; 1400 – 1800 m.

Conservation Status. Least Concern (LC).

subsp. scabrifolia (S. Moore) Goyder (2001: 159).

A. scabrifolia S. Moore (1908: 297). Type: Zimbabwe, Chimanimani Mts, 26 Sept. 1906, Swynnerton 1915 (holotype BM).

Distribution. Known only from the Chimanimani and Vumba massifs of eastern Zimbabwe and the outlying ranges in Mozambique.

Selected Specimens. See specimens cited by Goyder (2001: 159).

Habitat. Open grassland; 1200 – 2200 m.

Conservation Status. Least Concern (LC). Although known from a relatively restricted area, many of the localities are in formally protected areas, and there seems little direct threat to the overall population.

Notes. This subspecies can be distinguished from the former by its smaller flowers and shorter corona lobes. The clearest difference, however, concerns the coronal papillae which occur over most of the cavity of the lobe. In subsp. cucullata, these papillae are restricted almost entirely to a narrow band across the base of the lobe.

35. Asclepias pygmaea N. E. Br. (1895b: 255). Type: Tanzania, the lower plateau N of Lake Malawi [Lake Nyassa], Thomson s.n. (holotype K).

Distribution. Known only from the southern highlands of Tanzania and the Nyika Plateau in Malawi.

Specimens Examined. Tanzania. T7: Iringa Distr., Sao, 20 July 1933, Greenway 3428 (EA, K); Sao Hill, Oct. 1963, Procter 2415 (EA); Mufindi, 28 Sept. 1968, Harris & Paget-Wilkes 2368 (EA) & Oct. 1968, Paget-Wilkes 196 (EA); Mufindi West, Sept. 1959, Procter 1401 (EA); 70 miles from Iringa towards Mbeya, 6 Nov. 1969, Batty 825 (K); Njombe – Iringa, Aug. 1965, Beecher 97 (EA); lower plateau north of Lake Malawi, Thomson s.n. (holotype K). Malawi. N: Nyika Plateau, S slopes of Nganda, 13 Sept. 1972, Synge s.n. in WC 465 (K); Nyika Plateau, Chelinda Camp, 27 Oct. 1958, Robson 424 (K); Nyika Plateau, 4 Nov. 1975, Phillips 99 (K).

Habitat. Montane grassland; 1800 – 2500 m.

Conservation Status. Vulnerable VU B2ab(iii). Populations on the Nyika Plateau are well protected by the National Park, but it is likely that the Tanzanian localities are now badly degraded, with no collections since the 1960s. I have therefore assessed the status of this species as Vulnerable under Criterion B of the IUCN Red List Categories and Criteria (IUCN 2001).

Notes. Asclepias pygmaea was included by Bullock (1956) in synonymy with Trachycalymma cucullatum but excluded by Goyder (2001: 157 – 159) on the basis of the shape of the corona lobes, which are much longer than tall, and the coronal papillae which are distributed along the entire length of the lobes. It can also be easily confused with A. randii. A. pygmaea tends to have a more erect habit than A. randii, and stem and leaf indumentum is of short curled hairs not the stiff spreading hairs of A. randii. The flowers are slightly smaller and the corona has a less drawn-out apex, but are otherwise very similar. However, the pollinarium differs in having clearly differentiated proximal and distal portions to the translator arms, very slender and ± terete distally. The translator arms of A. randii are flattened, and broaden gradually towards the pollinia.

36. Asclepias densiflora N. E. Br. (1902: 320). Type: Zimbabwe, between Harare [Salisbury] and Bulowayo, Nov. 1899, Cecil 78 (holotype K).

Distribution. Zimbabwe, northern South Africa (Limpopo, NW Province, Gauteng, Mpumalanga, KwaZulu-Natal) and Swaziland.

Selected Specimens. Zimbabwe. W: Plumtree, Eyles 8549 (K); C: 12 km SE of Gweru [Gwelo], 14 Nov. 1966, Biegel 1436 (K); Macheke, Dec. 1919, Eyles 2021 (K, SAM); Rusape, Hislop Z225 (K); Section E, Dudley Estate, 22 km S of Marondera [Marandellas], fr. 24 Feb. 1976, Huntly s.n. in GH 265939 (K, SRGH); E: Mutare [Umtali] Commonage, 19 Nov. 1955, Chase 5900 (K, SRGH); SW portion of Mutare [Umtali] Golf Course, 30 Nov. 1960, Chase 7413 (K, NU, SRGH).

Habitat. Mixed Brachystegia woodland or wooded savanna, often on stony soil, sometimes persisting in cultivated land. In southern Africa it occurs in savanna and open grassland; 1000 – 1500 m in Zimbabwe, down to c. 600 m in South Africa.

Conservation Status. Least Concern (LC).

37. Asclepias adscendens (Schltr.) Schltr. (1896: 455). Type: South Africa, near Barberton, Oct. 1889, Galpin 596 (holotype B†; isotypes K PRE).

Gomphocarpus adscendens Schltr. (1894: 16).

Distribution. Swaziland, Lesotho and the north-eastern provinces of South Africa (Limpopo, NW Province, Gauteng, Mpumalanga, Free State, KwaZulu-Natal), with three collections from the eastern highlands of Zimbabwe.

Selected Specimens. Zimbabwe. E: Mutare [Umtali] Golf Course, 3 Jan. 1949, Chase 1891 (BM, K, SRGH); SW portion of Mutare [Umtali] Golf Course, 30 Nov. 1960, Chase 7663 (K, SRGH); maPanda’s Kraal, Oct. 1934, Gilliland 941 (BM).

Habitat. Open grassland, often in stony soil; 1000 m.

Conservation Status. Least Concern (LC).

Notes. Smaller and more branched than the preceeding species, habit more decumbent. Peduncles are much shorter in this species than in Asclepias densiflora, and the corona appears somewhat less fleshy. The follicle has more discrete processes rather than the irregularly lobed wings of A. densiflora.

38. Asclepias meliodora (Schltr.) Schltr. (1896: 455). Type: South Africa, Limpopo [Transvaal], near Sandloop, 3 Feb. 1894, Schlechter 4373 (holotype B†); Limpopo [Transvaal], N of Potgietersrust, 18 Dec. 1928, Hutchinson 1944 (neotype K, designated here).

Gomphocarpus meliodorus Schltr. (1895a: 33).

Asclepias meliodora (Schltr.) Schltr. var. brevicoronata N. E. Br. (1908: 700). Type: South Africa, NW Province, near Rustenburg, Pegler s.n. in Bolus 10553 (holotype K; isotype BOL, not seen).

Distribution. SE Botswana, South Africa (Limpopo, NW Province, Gauteng, Mpumalanga, KwaZulu-Natal), Swaziland and the neighbouring region of Mozambique.

Selected Specimens. Mozambique. M: near Goba, 19 Dec. 1952, Myre & Carvalho 1399 (K). Botswana. SE: Lobatse, Rogers 6244 (BOL, not seen — cited by Nicholas (unpublished ms)).

Habitat. Open grassland or scrub woodland, frequently on stony ground; c. 1200 – 1300 m in Botwana, c. 200 – 400 m in Mozambique.

Conservation Status. Least Concern (LC).

Notes. In designating a neotype for Gomphocarpus meliodorus Schltr., I have chosen a specimen from as close to Schlechter’s original locality as possible. Most collections look like a dwarf version of Asclepias adscendens. However, the corona is more elongate and less compressed, and the peduncle is much shorter. Follicles are smooth, lacking wings and spine-like processes. Eastern populations appear taller, and with longer peduncles, particularly those from the lower nodes.

Unplaced name

Asclepias baumii Schltr. (1903).

I have not seen the type (Baum 699a), and it is not listed on the ALUKA website (http://www.aluka.org/). From the description, it could perhaps be a glabrous-leaved form of Asclepias randii S. Moore, or A. aurea (Schltr.) Schltr., or be allied to these species.