Trichanthecium striatissimum (C.E.Hubb.) Zuloaga

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, Phytotaxa 646 (3), pp. 230-264 : 253

12. Trichanthecium striatissimum (C.E.Hubb.) Zuloaga , comb. nov.

Panicum striatissimum Hubbard (1926: 250) .

Lectotype (designated as “holotype” by Clayton & Renvoize 1982: 491):— KENYA. Kenya Colony: western slopes of Mount Kenya, along trail from West Kenya Forest Station to summit, in the Bamboo zone, at about 3000 m elevation, 28 September–7 October 1909, E. A. Mearns 1766 ( K [ 000282466 !], isolectotype BR [ 0000008760616 !]) . Fig.11

Perennial, not tufted, culms 30–60 cm tall, slender, profusely branching, many noded, rooting and somehow decumbent near the base, then erect; internodes cylindrical, 1.5–3.5 cm long, greenish to purple, hollow, glabrous; nodes dark, glabrous. Sheaths striate, 1.5–4.5 cm long, sparsely pilose to glabrous, the margins shortly ciliate, more so toward the apex. Ligule membranous, 0.6 mm long, shortly laciniate at the apex. Blades linear, 1.2–2.8 × 0.2(–0.3) cm, involute, closely appressed to the culms, rarely spreading or deflexed, narrowed at the base, bluntly acute, pilose on the adaxial surface and glabrous on the abaxial one. Inflorescence a terminal, contracted, few flowered panicle, 1–4 × 1–3 cm; peduncle cylindrical, 3–5 cm long, glabrous, pulvini glabrous; first-order branches alternate, appressed to the main axis, spikelets solitary on flexuous, glabrous pedicels 2–9 mm long. Spikelets ovoid, 3–3.5 × 1.1–1.4 mm, dark, pilose toward the apex, otherwise glabrous, glumes and lower lemma with manifest nerves; lower glume ovate-lanceolate, 2.5–3.4 mm long, ¾ to as long as the spikelet, pilose toward the apex, otherwise glabrous, membranous, 5–7-nerved, the apex acute; upper glume and lower lemma subequal, acute; upper glume 7-nerved, pilose toward the apex, otherwise glabrous, membranous; lower lemma 5-nerved, glabrous, membranous, acute; lower palea elliptic, as long as the lower lemma, hyaline, glabrous; lower flower staminate, anthers 1.8 mm long. Upper anthecium narrowly ovoid, 2.3–3 × 1–1.2 mm, indurate, glabrous, shiny. Caryopsis not seen.

Distribution and habitat: —This species is present in western tropical Africa, in Guinea, and eastern tropical Africa, from Democratic Republic of Congo to Tanzania and Uganda. It grows on rocky slopes and swamp meadows, at 2300–3250 m elevation.

Typification: —Another syntype of this species is: E. A. Mearns 1682 (B [10_0168674!], F [0046937F!], G [00022431!], GH [00024172!], K [000282465!], US [00148036!], W [19280008778!]).

Note: — Trichanthecium striatissimum was considered, as P. striatissimum , to be a synonym of T. eickii (≡ P. eickii ) by Clayton & Renvoize (1982). Later, Renvoize (1989b) correctly distinguished the species as valid, characterized by its linear to filiform blades, and spikelets 3–3.5 mm long.

Representative specimens examined: — BURUNDI. Mayuyu, Mont Heha , 7 Apr 1969, Lewalle 3455 ( BR) ; Prov. Muramvya: Teza, mont Ngoma , 4 May 1976, Reekmans 5013 ( BR) . DEMOCRATIC REPUBLIC OF CONGO. Karisimbi , 1929, Scaetta 1591 ( P) ; Mt. Muhi , vallée près du sommet, July 1948, Hendrickx 5200 ( BR) ; Kivu, Volcan Mikeno , April 1929, Humbert 8063 ( BR) ; Karisimbi, Parc National Albert, 1929, Scaetta s.n. ( K, P) . GUINEA. Friguiagbé , 6 September 1938, Chillon 703 ( P) . KENYA. Kenya. Bamboo zone, western slopes of Mount Kenya, along trail from West Kenya Forest Station to summit, at about 3000 m elevation, 28 September 1909, Mearns 1750, 1760 (paratypes, K), 1766 (paratypes, BR, K) . RWANDA. Par des Volcans, Karisimbi , 12 February 1975, D´Arcy 7716b ( MO, P) ; Volcan Karisimbi , au NE du Lac Kivu, June 1929, Humbert 8574 ( BR, P) . TANZANIA. Udzungwa Mountain, Luke et al. 6969 ( K) . UGANDA. Kashenyi, Lake Banyoni , 28 November 1935, Johnston 1360 ( BR) ; Behungi, Kigezi , 23 December 1933, Thomas 1194 ( K) .

Figures

FIGURE 11. Trichanthecium striatissimum. A. Habit. B. Ligular region. C. Detail of a branch of the inflorescence. D. Spikelet, ventral view. E. Spikelet, dorsal view. F. Lower glume. G. Lower palea. H. Upper anthecium, dorsal view. I. Upper anthecium, ventral view. J. Upper palea with stamens. (Humbert 8574 BR).