Urochloa reptans

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 : 232-233

30. Urochloa reptans (L.) Stapf in Oliv., F l. Trop. Afr. 9: 601. 1920 (F ig. 14E–F).

Panicum reptans L., Syst. Nat. ed. 10, 2: 870. 1759.

Brachiaria reptans (L.) C.A. Gardner & C.E. Hubb., Hooker’s Icon. Pl. 34: tab. 3363. 1938.

Lectotypus (first step designated by HITCHCOCK & CHASE, 1910: 36; second step designated by VELDKAMP, 1996: 427): COUNTRY UNKNOWN: sine loco, Browne s.n., Herb. Linn. No. 80.52, upper specimen ( LINN-HL80-52 image!) .

Annual to short-lived stoloniferous perennial, ascending to erect, to 0.6 m high, culms weakly branched, rooting at lower nodes, glabrous or pubescent, nodes finely hirsute. Leaf sheath glabrous or sparsely pubescent with ciliate margins. Ligule a line of hairs. Leaf blade ovate to lanceolate, basally cordate, chartaceous, 1–6 × 0.3– 1.2 cm, glabrous to sparsely hirsute on both sides, sometimes with bulbous-based trichomes near base. Inflorescence racemose, slender, open or contracted, 3–5 cm long. Racemes 4–15, 1–3.5 cm long, decreasing in length upwards on a common axis 1–3 cm long, sometimes with secondary branchlets, rhachis triquetrous, less than 0.5 mm wide, scaberulous to pubescent, spikelets overlapping untidily with adjacent spikelets, single, on pedicels of uneven length, subtended by white cilia. Spikelets ovate, apically acute, 1.7–2 mm long, yellow-brown to purpleish. Lower glume c. ¼ as long as spikelet, membranous, truncate, with no veins, glabrous, orientation relative to rhachis variable. Upper glume as long as spikelet, membranous, 5–7-veined, glabrous. Lower floret infertile, palea as long as lemma. Lower lemma membranous, 5–7-veined, glabrous. Upper lemma rounded, rugulose, mucronate.

Distribution and ecology. – Pantropical known weed with Malagasy populations of unknown origin. West Madagascar, especially abundant in north Madagascar where it often forms a dominant contribution to grazing lawn turf. Coastal grasslands and grazing lawns, secondary vegetation and roadsides, dry forest understory, often on sand, at elevations of 0–300 m (F ig. 17).

Notes. – The young inflorescences of Urochloa reptans are frequently purple in a way not usually seen in other species. Urochloa reptans displays a remarkable range of sizes, with smaller plants that appear reproductively immature still capable of producing clearly separated and reproductively functional spikelets on apical racemes. The mucro on the upper lemma appears to be sometimes absent.

According to the Linnean typification project [https:// www.nhm.ac.uk/our-science/data/linnaean-typification]: “Veldkamp (in Blumea 41: 429. 1996) followed Hitchcock (in Contr. U. S. Natl. Herb. 12: 119. 1908) in regarding this and P. reptans L. (1759) as homotypic. However, the first clear type choice dates from Hitchcock & Chase (in Contr. U. S. Natl. Herb. 15: 36. 1910), later restricted to the upper specimen on the sheet by Veldkamp”.

Selected specimens examined. – MADAGASCAR. Reg. Atsimo-Andrefana [Prov. Toliara]: vallée du F iherenana, III.1960, Bosser 14019 ( P); Ankazo-abo-Sud , F otivolo, II.1963, Bosser 17952 ( P). Reg. Boeny [Prov. Mahajanga]: Ambato Boeny , XI.1951, Bosser 2012 ( K, P); Androhibe , I.1967, Granier & Delhaye 112 ( P); Basalle - Antanimena plateu, I.1924, Perrier de la Bâthie 15919 ( P). Reg. Aiana [Prov. Antsiranana]: Nosy Be , IV.1879, Hildebrandt 2928 ( K, P); commune Antsahampano , fokontany Antongombato, Antamotamo, 3.III.2015, Vorontsova et al. 1840 ( TAN). Reg. SAVA [Prov. Antsiranana]: Vohemar, Daraina Protected Area office grounds, 12.X.2011, Vorontsova et al. 352 ( K, TAN); outside Montagne d’Ambre Parcelle 1. Reg. Sofia [Prov. Mahajanga]: Moramandia , Andranosamantana, 28.II.1923, Decary 1468 ( P) .