Trichanthecium wiehei Zuloaga, comb. nov.
Creators: name: Zuloaga, Fernando Omar
name: Aliscioni, Sandra
name: Delfini, Carolina
name: Salariato, Diego Leonel
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Poales
Poaceae
Trichanthecium
Trichanthecium wiehei

description: 13. Trichanthecium wiehei (Renvoize) Zuloaga, comb. nov.
Panicum wiehei Renvoize (1980: 554).
Lectotype (here designated):— MALAWI. Slopes of Dedza Mountain, 27 March 1950, P. O. Wiehe N/469 (K [000255525!], isolectotypes K [000255526!], K [000255527!]).
Annual, not tufted; culms decumbent, branching and rooting at the lower nodes, then erect, (30–) 50–90 cm; internodes cylindrical, 2–4 cm long, hollow, sparsely pilose to glabrous; nodes compressed, dark, shortly pilose to glabrous. Sheaths striate, 2–6 cm long, sparsely pilose, with long hairs near the junction with the blade, the margins shortly ciliate. Ligule membranous, 0.5–0.6 mm long. Blades ovate-lanceolate, 2–15 × 0.4–1.6 cm, flat, cordate at base, shortly pseudopetiolate, pseudopetiole short to long pilose, membranous to herbaceous, pilose, with tuberculate hairs, to glabrous, acute, the lower margins ciliate, otherwise scabrous, midnerve manifest. Inflorescence a terminal, open to contracted panicle, 7–14 × 6–10 cm; peduncle cylindrical, 5–15 cm long, glabrous; pulvini dark, glabrous; main axis sparsely pilose to scabrous, first-order branches alternate, divergent to congested, axis of the branches scabrous, spikelets solitary on scabrous pedicels 1–6 mm long. Spikelets ellipsoid, 2–2.5 × 0.9–1 mm; lower glume 0.5–0.7 mm long, 1/4 to 1/3 the length of the spikelet, nerveless to 1-nerved, sparsely pubescent to glabrous, acute to obtuse, membranous; upper glume and lower lemma subequal, sparsely pubescent to glabrous, membranous, 5-nerved, the midnerve scabrous; lower palea elliptic, 1.8–2.2 × 0.8–0.9 mm, as long as the lower lemma, hyaline, glabrous, the margins scaberulous; lower flower staminate, anthers 1.6 mm long. Upper anthecium ovoid, 1.8–2.1 × 0.7–0.9 mm, glabrous, indurate, smooth, shiny. Caryopsis not seen.
Distribution and habitat: —Species present in Malawi, Southern Sudan, and Zimbabwe, where it grows in forest margins, scrambling over shrubs in the forest, and riverine woodland; at 1700–2200 m elevation (Renvoize 1980).
Typification: —The protologue of Panicum wiehei cites a single collection, Wiehe N/469 at K as the type. However, at K there are three sheets. Therefore, we selected one of them, K [000255525!], as the lectotype.
Note: — Trichanthecium wiehei is morphologically similar to T. calvum, the latter differing by having a lower glume of 1/2 to 2/3 times the length of the spikelet, 1–3-nerved, acute, and by the lack of a lower palea.
Representative specimens examined: — MALAWI. Zomba plateau, Lawrence 290 (K); Mutare, Murahwa’s Hill, 22 March 1970, Simon 2118 (K). SOUTHERN SUDAN. Near Gilo village, Friis & Vollesen 8 (K). ZIMBABWE. Inyanga, Honda Valley, Phipps 1115 (K); Mutare (Umtali), Vumba Mountains, Fisher 1535 (K).
description: Published as part of Zuloaga, Fernando Omar, Aliscioni, Sandra, Delfini, Carolina & Salariato, Diego Leonel, 2024, Old World species of Trichanthecium (Poaceae: Panicoideae: Paniceae) including a new species from the Democratic Republic of Congo, pp. 230-264 in Phytotaxa 646 (3) on page 255, DOI: 10.11646/phytotaxa.646.3.2, http://zenodo.org/record/13215433