Urochloa mutica

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 : 229

24. Urochloa mutica (F orssk.) T.Q. Nguyen in Novosti Sist. Vyssh. Rast. 1966: 13. 1966.

Panicum muticum F orssk., F l. Aegypt.-Arab. 20. 1775.

Brachiaria mutica (F orssk.) Stapf in Oliv., F l. Trop. Afr. 9: 526. 1919.

Holotypus: EGYPT. Beheira: Rashid, XI.1761, Forsskål 86 ( C [ C10002726 ] image!; iso-: BM) .

Stoloniferous perennial, ascending to erect, 0.25–1.25 m high, culms weakly branched, rooting at lower nodes, glabrous, nodes prominently bearded. Leaf sheath glabrous to pubescent. Ligule a line of hairs. Leaf blade linear, thickly chartaceous, 6 – 30 × 0.3– 1.5 cm, glabrous to pubescent on both sides. Inflorescence racemose, pyramidal, open, 10–30 cm long. Racemes 5–20, 2–10 cm long, decreasing in length upwards, on a common axis 7–20 cm long, with short secondary branches on lower racemes, rhachis narrowly winged, 0.5–1 mm wide, scabrid, spikelets overlapping with adjacent spikelets, paired near base and single towards apex of racemes, subsessile, in several untidy rows, subtended by a few cilia. Spikelets elliptic, apically acute to acuminate, 2.5–3.5 mm long, yellowish to purple. Lower glume ¼–⅓ as long as spikelet, membranous, acute, 1–3-veined, glabrous, orientation relative to rhachis variable. Upper glume as long as spikelet, membranous, 5–7-veined, glabrous. Lower floret male, palea as long as lemma, anthers 3, c. 1.8 mm long. Lower lemma membranous, 5-veined, glabrous. Upper lemma obtuse, rugulose, minutely mucronate.

Distribution and ecology. – The origin of this easily recognisable pantropical forage is not fully clear. At least some of the known localities are introductions; Boivin recorded it as “naturalised” on Mauritius in 1851 [P06769193]. Damp habitats in fields and secondary vegetation (F ig. 15).

Notes. – Urochloa mutica is recognised by its tall stature and its pyramidal inflorescences with an untidy arrangement of spikelets on the racemes.

Selected specimens examined. – MADAGASCAR. Reg. Sofia [Prov. Mahajanga]: Bealanana , Betainkankana , Ankaizina, V.1952, Bosser 2557 ( P). Reg. Boeny [Prov. Mahajanga]: Mahajanga Ville , Amborovy, 8.V.1962, Boudet 1277 ( P); Marovoay , IMVPT 890 , 9.V.1962, Boudet 4283 ( P). Reg. AlaotraMangoro [Prov. Toamasina]: Ambatondrazaka , introduced, 7.III.1932, Jard. Bot. Tananarive 324119 ( P) .