Trichanthecium aequinerve 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 aequinerve

description: 2. Trichanthecium aequinerve (Nees) Zuloaga, comb. nov.
Panicum aequinerve Nees (1841: 40).
Lectotype (here designated):— SOUTH AFRICA. Cape Province, “In graminosis inter Morley et Omtata alt. 1000–2000”, J. F. Drege 4290 (P [00442137!]).
Panicum perlaxum Stapf (1899: 400).
Lectotype (here designated):— SOUTH AFRICA. Coastal Region: Albany Div.: Coldspring near Grahamstown, H. G. Flanagan 766 (K [000255485!]).
Annual or short-lived, not tufted perennial; culms slender, 15–60(–90) cm long, scrambling, decumbent and rooting at the lower nodes, then ascending; internodes cylindrical, 3–8 cm long; nodes compressed, dark, glabrous. Sheaths striate, 3–7 cm long, longer or shorter than the internodes, densely hirsute, the upper margins long ciliate. Ligule membranous, 0.5 mm long, brownish, with long hairs up to 5 mm long behind the ligule and at the base of the blade. Blades narrowly lanceolate, 3–11(–20) × 0.3–0.9(–1.1) cm, narrowed at the base, flat, herbaceous glabrous to densely hirsute, acute or acuminate, narrowed into a short pseudopetiole, pseudopetiole shortly pilose, the margins ciliate. Inflorescence a terminal exserted panicle, broadly ovate, 4–15(–20) × 4–15 cm; peduncle cylindrical, 6–20 cm long, pilose; first-order branches alternate or subopposite, hirsute, spikelets solitary on first- and second-order branches, pedicels 2–5 mm long, flexuous, pilose. Spikelets narrowly ovoid, 2.5–3 × 1 mm, dark brown at maturity; lower glume ovate, almost as long as the spikelet, 3(–5)-nerved, acute, pubescent, upper glume ovate, 7-nerved, acute, pubescent; lower lemma 5-nerved, membranous, acute, pubescent, lower palea elliptic, 2.4–2.6 × 0.6 mm, hyaline, glabrous, to reduced; lower flower staminate to neuter. Upper anthecium ovoid, 2.3–2.8 × 1 mm, pale, indurate, shiny, smooth and glabrous. Caryopsis not seen.
Distribution and habitat: —Species widely distributed from Ethiopia to South Africa, where it is found in shade of forest margins, rocky slopes or grassland on clay or sandy soils; at 200–2600 m elevation.
Chromosome number: —n = 18 (Spies et al. 1991).
Typification: —When describing Panicum aequinerve, Nees mentioned two collections made by Drege in South Africa, of which P00442137 is here selected as the lectotype since it agrees with the protologue of the species and includes a full specimen.
Another syntype of P. aequinerve is: “Graminibus altis immixtum inter Omsamculo et catarractas maiores pari altitudine ...”, J. F. Drège s.n. (HAL [0082518] image!, P [00442136] image!).
Stapf (1920) cited three South African syntypes in his description of P. perlaxum; of these, Flanagan 766, K000255485, is here designated as the lectotype. Another syntypes of this species are: South Africa. Eastern Region: Tembuland; near Morley, 1000–2000 ft, J. F. Drège s.n. (K000255484!). Natal: coastland, Sutherland s.n. (K000255847!).
Note: — Brown (1977) reported that this is a non-Kranz species with a ₰13C value of –26.7.
Representative specimens examined: — BURUNDI. Bujumbura: Karinzi, route Gakara-Bujumbura, 8 June 1979, Ndabaneze 706 (BR, K); Muberure, 11 May 1985, Ndabaneze 1795 (BR). ETHIOPIA. Kaffa. Mount Maigudo, ca. 40 km from Jimma-Addis Adeba road on Omo-Nadda track, Friis et al. 1443 (K); Jimma, Stewwen 172 (K). MALAWI. Mlanje Mountains, Lichenya Plateau, 8 June 1962, Robinson 5310 (K). RWANDA. Route Gitarama-Ruhengeri, 13 km de Gitarama, 21 May 1970, Bouxin & Radoux 2145 (BR). SOUTH AFRICA. Cape. Cap de Bonne Espérance, Drége s.n. (P 002250417); Fort Beaufort, Fort Fordyce, Story 2109 (K). Natal. Nkandhla, Gudeni Forest Reserve, 19 February 1940, Fisher 13 (K, US); District Babanango, 17 km SSW of Mahlabatini, 14 January 1948, Acoks 13969 (BR); 33 km S of Nqutu along road o Kranskop, 23 February 1974, Davidse 6858 A (MO); Mkambati Nature Reserve, near mouth of Mkambati River, 10 December 1986, Smook 6052 (US); 42 km from Underberg on road to Nottingham Rd., 16 January 1980, Smook 1674 (US); 10 km from Louwsburg on road to Pongola Grassland, 9 January 1980, Smook 1568 (US); Ngome Forest, 8 January 1980, Smook 1550 (US); Van Reenens Pass, January 1980, Smook 1216 (K). Transvaal. Near summit of Wolkberg propei, SE of Haenetsburg, Meeuse 9902 (K); 1 km E of Steilkop, New Agatha Forest Reserve, Muller & Scheepers 30 (K). UGANDA. Bwanda Pass, Toro, Thomas 1416 (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 pages 238-239, DOI: 10.11646/phytotaxa.646.3.2, http://zenodo.org/record/13215433