zyxwvutsr Berlin, M k z 1995 Feddes Repertorium 106 (1995) 1-2.7- 12 Rheinische Friedrich-Wilhelms-Universitat, Botanisches Institut und Botanischer Garten, Bonn, Deutschland zyxwvu zyxwvutsrqp R. SEINE; E. FISCHER; W. BARTHLOI-T Notes on the Scrophulariaceae of Zimbabwean inselsbergs, with the description of Lindernia syncerus sp. nov. zyxwvutsr zyxwvutsrq zyxwvut With 3 Figures and one Table S u m mary Zusarnmenfassung An account of the 19 Scrophulariaceae found on Zimbabwean inselbergs is given, based on studies of 53 inselbergs. Habitat preferences and importance of inselbergs as habitats are discussed. Lindernin syncerus SEINE, FISCHER & BARTHLOTT from Urnfurudzi Safari Area is described. The new combination Crepidorhopulon debilis (SKAN) FISCHER is made, the occurrence of the species is reported for the Flora Zambesiaca Area for the first time. Die vorliegende Arbeit gibt einen Uberblick uber die Scrophulariaceen, die auf Inselbergen in Zimbabwe gefunden wurden. Auf 53 Inselbergen konnten insgesamt 19 Scrophulariaceen-Arten nachgewiesen werden. Die bevorzugten Habitate und die Bedeutung von Inselbergen als Wuchsone werden diskutiert. Lindernin svncerus SEINE,FISCHER & BARTHLOTT aus der Umfurudzi Safari Area wird neu beschrieben. Crepidorhopalon debilis (SKAN)FISCHER wird neu kombiniert, die Art wurde erstmals fur das Gebiet der Flora Zambesiaca nachgewiesen. Introduction BARTHLOTT et al. 1993; POREMBSKI et al. 1994). & BARTHLOTT(1992) describe the POREMBSKI vegetation on inselbergs in Western Africa: cryptogamic crusts, drainage channels, rock crevices and boulder falls, rock pools, flat depressions (with a shallow layer of skeletal soil), deep depressions (filled with soil), monocotyledonous mats, ephemeral flush vegetation, and wet flush vegetation. The same types of habitats are also found on inselbergs in Zimbabwe. Studies of inselberg vegetation in Zimbabwe were conducted as a contribution to the “Inselberg-Projekt” (supported by the Deutsche Forschungsgemeinschaft). Field work was carried out 1993 and 1994 on 53 inselbergs throughout Zimbabwe. With nineteen species Scrophulariaceae were among the most specious angiosperm families on inselbergs. PHILCOX (1 990) treated the Scrophulariaceae for the Flora Zambesiaca area. The African Lindernieae were revised by FISCHER (1992). The present work gives a survey of Scrophulariaceae Inselbergs are isolated rock outcrops that stand above the surrounding plains. Their flanks are more or less curved and expose bare rock surfaces. Inselbergs have been studied in depth geomorphologically (for a survey see BREMER& JENNINGS 1978).They are old landscape elements which may exceed 10 million years of age. Zimbabwe harbours a large quantity of granitic and gneissic inselbergs. In some parts of the country (e.g. the Matopos and the Masvingo area) they dominate whole landscapes. Inselbergs are edaphically dry habitats: Water capacity is low due to the scarce soil cover and in addition the rock surface heats up considerably during insolation. The vegetation cover of inselbergs is distinctly different from the vegetation of the surrounding plains (BARTHLOTT et al. 1993).Recently, inselberg vegetation has attracted special attention as a model system for studies on biodiversity (POREMBSKI& BARTHLOTT 1992; zyx zyx zy zyxw zyxwvuts Feddes Repert., Berlin 106 ( 1 995) 1-2 on Zimbabwean inselbergs, their habitat preferences, restriction to inselbergs, and some notes on their ecology. Within the ephemeral flush vegetation, a conspicuous new species ofliiicleriiia was collecfed. It is so distinctive, showing a staminodium type hitherto not known in the genus that we do not hesitate to describe it as a new species although it is only known from the type. Lindernia syncerus SEINE, FISCHER & BARTHLOTT Sp. nOV. Ty p u s: Seine 1 197, Urnfurudzi Safari Area, Zimbabwe (K-, Holotype). Liiidernia exili et schweiizjkrrizii affinis, sed labio superiore indiviso antheris pilosis et staminodiis abaxialibus clavatis symplicatis minute cornutis et subtus longe hirsutis valde differt. Annual plant, stem up to 6 cm high, quadrangular. Leaves linear to lanceolate, stem leaves 8,5-9,5 x 0,6-0,7 mm, apex +/-obtuse with minute hairs and tinged with purple, basal leaf pair 5 3 x 0,s-0,9 mm. Florescence a lax, few flowered raceme. Pedicel up to 8,5 mm long. Calyx 2 mm long, free sepals 1,8 mm long, acute, apex with minute hairs and tinged with purple. Corolla glabrous, orange, lower lip with violet mark and two yellow spots, gorge violet. Upper lip 3 mm long, entire. Lower lip tripartite, each lobe 2 mm long. Adaxial (posterior) stamina with anther symplexus, filaments 1,9-2 mm long, adaxial thecae with few short hairs, 0,7-0,s mm long, abaxial thecae with many hairs, 0,3-0,4 mm long. Abaxial (anterior) stamina sterile, reduced to staminodia, dark violet, with a symplexus of the clavate apex. Filaments 1,5-1.8 mm long, with geniculations (Cruterostigrna type) fused with lower lip and covered with yellow glands and papillae, apex of staminodes anther-like, clavate, 0,5-0,8 mm long, with a minute horn and 0,5 mm long hairs on the lower side. Ovary ovate, 0,8-1 mm long, style 3 mm long, stigma bilobed, 0,5 mm long. Seed not known. Illustration: Fig. 1. habitat shows strong seasonality: During the rainy season the soil is waterlogged while it dries out completely during the dry season. Most species in this habitat are annual and reproduce from seed. The ephemeral flush vegetation is characterised by small Cyperaceae, Eriocaulaceae, Llfriculurin spp., and Drosera indicn. N o t e : Two specimens from Zimbabwe cited by PHILCOX (1990), Greatrex in GHS 18384 and Whelan 1222 (both SRGH, Harare), might prove to belong to this species. Crepidorhopalon debilis (SKAN) FISCHER comb. nov. B a s i o n y rn: Lindernict debilis SKAN, Flora of Tropi- cal Africa IV, 2, 344. Typus: Schweinfurth 2516, (K). This species was described as Lindernia debilis by SKAN(1906). Recent investigation of material from the Cote d’Ivoire and Zimbabwe revealed aulacospermous seeds and the typical club-shaped hairs with multicellular socle on the lower lip of corolla. In a modem systematic concept it is best placed in Crepidorhopalon FISCHER. It is here reported for the Flora Zarnbesiaca Area for the first time: Plants were found on Mt. Pomongwe, Rhodes Matopos National Park, Zimbabwe (Seine 1096) and in Umfurudzi Safari Area, Zimbabwe (Seine 1185). H a b i tat: Crepidorhopalon debilis grows in an ephemeral flush community on granite inselbergs. The species shows a sudano-zambesian distribution. Scrophulariaceae on inselbergs in Zimbabwe zyxwvut zyxwvut Etyrno1ogy:Thenameischosen topointoutthe striking resemblance of the syrnplexed starninodia to the horns of the african buffalo, Syncerus caffer. Ha b i tat: Lindernia syncerus grows in an ephemeral flush community on granite inselbergs. This Nineteen species of Scrophulariaceae were found on inselbergs in Zimbabwe. They are predominantly growing in rock crevices, flat depressions, ephemeral flush vegetation, and rock pools. Species of flat depressions are occasionally found growing on the flat margins of monocotyledonous mats and deep depressions. Other habitat types are of minor importance to Scrophulariaceae. zy zy zyxw zyxwvu zyxwvuts R. SEINE et al., Scrophulariaceae of Zirnbabwian insetbergs 9 /--.. i d I E E ln \ Fig. I Lindernia syncerus zyxw E E I- zyxwv A - habit; B, C - flower; D, E - adaxial stamina; F, G - abaxial stamina. Drawn from the Holotyp by E. Fischer 10 zyx zy Feddes Repert., Berlin 106 (1995) 1-2 zyxwvutsrq Therophytes are the prepondering life form. The five perennial species are poikilohydric resurrection plants from the genera Lindernia and Craterostigma. The latter genus shows an interesting distribution on inselbergs in Zimbabwe : Craterostigma lanceolaturn (ENcL.) SKANwas only found in the Eastern Highlands while Craterostigma plantagineiim HOCHST. was found quite regularly throughout the country. The majority of species is restricted to inselbergs or has been regularly found on inselbergs. Only five species show a wider ecological range. Various patterns of distribution occur: Species are Southern African [e.g. Lindernia confertn (HIERN)PHILCOX (Fig. 2), Lindernia monroi ( S . MOORE) FISCHER (Fig. 3)], Southern and Eastern African [e.g. Lindenzia piilchella (SKAN) PHILCOX], sudano-zambesi an [e .g . Lindernia Crepidorhopalon debilis (SKAN) exilis PHILCOX, FISCHER], or palaeotropic [e.g. Srriga asiatica (L.) KUNTZE]. Detailed information is compiled in the Table. Discussion The habitats in which Scrophulariaceae occur on inselbergs in Zimbabwe are generally dominated by annual species. The plant cover is relatively sparse, leaving open soil for seedling establishment. The other habitat types of inselbergs are dominated by perennial species and show a dense cover of vegetation. As most Scrophulariaceae on inselbergs are small therophytes they do not seem to be able to establish populations among dense vegetation. The same might be true for the perennial poikilohydric species. The parasitic or hemiparasitic species Alectra orobanchoides BENTH., Biichnera specioscr SKAN,and S t r i p asirrtica were found in deep depressions or monocotyledonous mats dominated by perennials. They are not restricted to inselbergs (PHILCOX 1990) and probably grow wherever a suitable host is encountered. Striga gesnerioicies (WILLD.)VATKEis found in rock crevices because it has an affinity to Indipofera, Table Distribution, habitat, life form, and restriction to inselbergs Species Distribution Habitat Alectra orobanchoides Buchnera speciosu Craterostigma lanceolatum Craterostigma pluntngineurn Crepidorhopalon debilis Crepidorhopalon spicutus Dopatrium Juncerim Lindernia confertrr Lindernia exilis Lindenia monroi Lindernia nana Lindernia nummulariifolia Lindernia pulchellu Lindernia syncerus Lindernia wilmsii Striga asiatica Striga gesnerioides Rhamphicarpa brevipedicellata Rhamphicarpa fistulosa S- and E-Africa SE-Africa, Tanzania E- and SE-Africa Trop.-Africa, India sudano-zarnbesian sudano-zambesian palaeotrop.-australian S-Africa sudano-zambesian S-Africa S- and trop. Africa palaeotropic E- and S-Africa SE-Africa E- and S-Africa palaeotropic palaeotropic S- Africa pa1aeotrop.-australian 5 Lifeform IB-species 6 2 2 3 2 4 4 2 4 2 3 21516 3 216 516 1 3 3 zyxwvu zyxw zyxwvu zyxwv Habitat: I - rockcrevices; 2 - flat depressions; 3 - ephemeral tlush; 4 - rock pools; 5 -deep depressions, 6 - monocotyledonous mats. Life-form: a - annual: p - perennial. IB-species - main habitat not on inselbergs; (+) - regularly on tnselbergs, + - main habitat on inselbergs zyxwvuts R. SEINE et nl., Scrophulariaceaeof Zirnbabwian inselbergs 11 zyxwvutsrqp zyxwvutsrqpon Fig. 2 Lindernia conferta Tephrosia, and Merremia species (PHILCOX 1990) bergs forming island like habitats in the landscape may have influenced speciation of taxa that are often found in this habitat type. As noted above, Craterostigma lanceolatum restricted to these habitats. In the genus Linderand Craterostigma plantagineum have different nia, inselbergs of Southern Africa must be countpatterns of distribution on inselbergs in Zimbab- ed among the centres of diversity. The small ecological range of Scrophulawe. Both are growing in shallow depressions. C. lanceolatum is only found in high altitudes riaceae on Zimbabwean inselbergs makes them (above 1700 m) in the eastern highlands while potentially vulnerable to habitat destruction. In Craterostigma plantagineum is common on in- fact there is no danger of extinction as fortunately selbergs throughout the country (including lower many inselbergs are difficult to climb and thereparts of the eastern highlands). Reasons for this fore not used for grazing cattle or goats. Also a ecological vicariance might be the different cli- large number of inselbergs is found in protected mate with regular frosts and higher rainfall in areas such as National Parks ensuring adequate higher altitudes. In other regions of Africa e.g. habitat conservation. Rwanda both species are sympatric. Geographically vicariant taxa are known for A c k n o w l e d g e m e n t s Lindernia conferta (Lindernia natans FISCHER We gratefully acknowledge financial support by the from Madagascar), Lindernia monroi [Lindernia Deutsche Forschungsgerneinschaft (Ba 605/2) and a linearifalia (ENGLER) FISCHER from Angola], and scholarship granted to R. SEINEby the Studienstiftung Crepidorhopalon debilis [Crepidorhopalon des deutschen Volkes. The National Research Council microcarpaeoides (BONATI)FISCHER from Ma- of Zimbabwe is thanked for permission to conduct dagascar]. The scattered distribution of insel- research. We also whish to acknowledge the invaluable zyx 12 Feddes Repert., Berlin 106 ( I 995) 1-2 zyxwvutsrqp zy Fig. 3 Lindernia mnnmi assistance of the Director and staff of the National PHILCOX, D., 1990, Scrophulariaceae. in: LAUNERT, E. ; Herbarium and Botanic Gardens, Harare, especially POPE,G. V., Flora Zambesiaca 8 (2). London. Dr. R. B. DRUMMOND, Dr. S. KATIVU, Dr. T. MULLER, POREMBSKI, S.; BARMLOTT,W., 1992, Struktur und and Dr. N. NOBANDA. The authors would also like to Diversitat der Vegetation westafrikanischer Inselthank Dr. S. POREMBSKI for discussions on the manuberge. Geobot. Kolloq.. 8,69-80. script. POREMBSKI, S.; BARTHLO~T, W.; DORRSTOCK, S.; N. BIEDINGER, 1994, Vegetation of rock outcrops in Guinea: granite inselbergs, sandstone table mountains, and ferricretes -remarks on species numbers References and endemism. Flora, 189,315-326. BARTHLOTT, W.; G R ~ G E R A.; , S. POREMBSKI, 1993, Some remarks on the vegetation of tropical inselbergs: diversity and ecological differentiation. Address of the authors: Biogeographica, 69 (3), 105-124. R. SEINE,E. FISCHER, Prof. D. W. BARTHLOTT, RheiniBREMER, H.; JENNINGS, J. (eds.), 1978, Inselbergs/In- sche Friedrich-Wilhelms-Universitat, Botanisches Inselberge. Berlin. stitut und Botanischer Garten, Meckenheimer Allee FISCHER, E., 1992, Systematik der afrikanischen Lin170,53225 Bonn, Bundesrepublik Deutschland. dernieae (Scrophulariaceae). Trop. Subtrop. Pflanzenw., 81, 1-365. Manuscript received: December, 22nd, 1994