Echinochloa leandriana (Bosser) Voronts.

Vorontsova, Maria S., 2022, Revision of some Malagasy forage grasses and their relatives within Brachiaria, Echinochloa, Moorochloa, and Urochloa, Candollea 77 (2), pp. 199-236 : 220-221

13. Echinochloa leandriana (Bosser) Voronts. , comb. nov.

Brachiaria leandriana Bosser in Adansonia, sér. 2, 6: 111. 1966.

Holotypus: MADAGASCAR. Reg. Atsimo-Andrefana [Prov. Toliara]: plateau Mahafaly, W de Ejeda, III.1960, Bosser 14538 ( P [ P00450182 ]!; iso-: [ P00450183 , P00450184 ]!, TAN!) .

Loosely tufted mat-forming stoloniferous perennial, ascending to erect, to 30 cm high, culms thickened and knotty at base, glabrous, nodes bearded. Leaf sheath pubescent, silky at base. Ligule absent. Leaf blade narrow-lanceolate, chartaceous, 4–8 × 0.3–0.7 cm, pubescent on both sides. Inflorescence racemose, thick, contracted or subcapitate, 3– 6 cm long. Racemes 4–7, 0.6–2.5 cm long, decreasing in length upwards, on a common axis 1 –4 cm long, with no secondary branching, rhachis triquetrous, finely pubescent, spikelets overlapping untidily with adjacent spikelets, paired, subsessile, in 4 untidy rows. Spikelets ovate, apically apiculate, 2–2.2 mm long, whiteish. Lower glume ⅔–¾ as long as spikelet, herbaceous, apiculate, 3–5-veined, hirsute, orientation relative to rhachis variable. Upper glume as long as spikelet, herbaceous, apiculate, 7–9-veined, veins pronounced, hirsute. Lower floret male, palea as long as lemma. Lower lemma herbaceous, 5–7-veined, hirsute. Upper lemma apiculate, smooth, shiny, pale.

Distribution and ecology. – Endemic to the Mahafaly plateau in arid inland southwestern Madagascar, forming spreading mats in open canopy secondary vegetation on limestone (F ig. 12).

Notes. – This species is known from only three collections by Jean Bosser and has not been seen since 1963. It is not clear why BOSSER (1966) described this material in the genus Brachiaria given its striking resemblance to Echinochloa, including the lack of ligule characteristic of Echinochloa illustrated in BOSSER (1966). Compared to Brachiaria and Urochloa s.l., this is a distinctive species with dense whiteish inflorescences and bearded nodes. Unpublished DNA sequences place it firmly in Echinochloa in the subtribe Boivinellinae (Bosser 16110, P02233533, G. Besnard & J. Hackel, pers. comm.). A full revisison of Echinochloa in Madagascar is beyond the scope of this work; the species is here transferred to Echinochloa pending a more detailed assessment of species boundaries.

Additional specimens examined. – MADAGASCAR. Reg. Atsimo-Andrefana [Prov. Toliara]: Ankalirano (Ankadirano), plateau Mahafaly , III.1962, Bosser & Viennot 16110 ( P); Betioky , Ekinaty, III.1963, Bosser 19687 ( P) .