Thesium fimbriatum A.W.Hill

Flora Zambesiaca. Vol. 9, Part 3. Polygonaceae-Myriaceae. Pope GV, Polhill RM, Martins ES. 2006.

Type

Type:Malawi, between Khondowe and Karonga, Whyte 321 p.p. (K, holotype).

Morphology General Habit

Possibly annual or perennial; stem 270–850 mm tall, (2.5)3–4 mm diameter at base, usually solitary, rarely 2–3 from woody crown, either simple or simple near base, soon virgately branched, the branches sharply ascending, strongly ribbed by raised vascular strands terminating in midribs of scale leaves and bracts, distantly leafy

Morphology Leaves

Leaves all reduced to scales, c. 0.5–2 × 0.4–1.6 mm, increasing in size upwards, distant below, becoming more crowded upwards and passing into floral bracts, lanceolate, acuminate, closely appressed, midrib strongly raised on dorsal surface

Morphology Reproductive morphology Flowers

Flowers sessile in axil of each bract, up to c. 10 crowded on a very short brachyblast, these either simple or branched, or sometimes in long many-flowered spikes, the flowers ± crowded below, distant above, both brachyblasts and long spikes sometimes present on one plant, the whole forming a panicle

Morphology Reproductive morphology Inflorescences Bracts

Bracts (lowermost) 2.4–3.5 × 1–2 mm, ovate-acuminate, margins membranous, minutely erose-ciliate, keeled by strongly raised midrib; bracteoles 2, similar to bracts

Morphology Reproductive morphology Flowers Pedicel

Pedicels wanting

Morphology Reproductive morphology Flowers Perianth

Perianth possibly creamy-yellow inside; tube 0.5–1 mm long, 5 tiny (c. 0.1 mm) tooth-like glands alternating with the lobes; lobes usually 5, sometimes 4, c. 1.5–2.7 × 0.4–0.6 mm at base, subspathulate, apex subobtuse to acute, hood c. 0.25(0.4) mm long, margins inflexed, fringed with long white hairs

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens inserted near base of perianth lobes; filaments conspicuous, c. 0.9–1.5 mm long, lower part adnate to perianth lobe; anthers 0.3–0.5 mm long

Morphology Reproductive morphology Flowers Gynoecium Style

Style c. 1.2–2.6 mm long; stigma reaching ± to middle of anthers

Morphology Reproductive morphology Fruits

Fruit 1.6–2 × 1.4–2 mm, buff-coloured to light reddish-brown, strongly ribbed, the 5 intermediate ribs often forking once near base, reticulations few and often obscure.

Ecology

Moist dambos or drier areas in grassland; c. 1370–1800 m.

Note

There are 4 specimens on the type sheet of T. fimbriatum. Hill segregated one of them as the type of the name and assigned the rest to T. stuhlmannii Engl. (type from Itiolo [misprint for Itolio in Bukoba Distr.] in NW Tanzania, west of Victoria Nyanza). The characters given to distinguish T. fimbriatum from T. stuhlmannii were its more bushy habit, more delicate branches, ovate acuminate ciliate bracts and linear elliptic perianth lobes, but these characters, apart from the delicate branches, apply equally well to the type specimen of T. stuhlmannii, which does, however, differ in its glabrous perianth lobes and tiny fruits (c. 1.2 × 1.7 mm). Whyte's three specimens assigned by Hill to T. stuhlmannii have the fimbriate lobes and slightly larger fruits of T. fimbriatum. Apparent differences in branching can be attributed to degree of development of brachyblasts, which may depend on the age of the plant: this needs field observation. Indeed, this whole difficult group (that is, those species with ovate acuminate bracts, clusters of sessile flowers, and tooth-like glands alternating with the perianth lobes, 5 species in the Flora Zambesiaca area, but many more in Angola, Dem. Rep. Congo and East Africa) needs study over a wide range of material. The type of T. shabense precisely matches that of T. fimbriatum. Both specimens often have the perianth lobes slightly longer than the other material included by me under T. fimbriatum (lobes up to c. 1.8–3 mm versus 1.4–2.2 mm) but all the material agrees in its relatively stout stems, often solitary, always simple below, branching above, fimbriate perianth lobes with only a small hood, and tiny (c. 0.1 mm) external glands. T. fimbriatum A.W. Hill in F.C. 5, 2: 191 (1915) is a later homonym, renamed T. brachystylum A.W. Hill in 1920.

Distribution

Mozambique Malawi ZAM N, ZAM W, ZAM C, MAL N, MOZ N Also in Katanga (Shaba) Province of Dem. Rep. Congo and Tanzania. Zambia