Urochloa pseudodichotoma (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 : 231

28. Urochloa pseudodichotoma (Bosser) Voronts. , comb. nov.

Brachiaria pseudodichotoma Bosser in Adansonia, sér. 2, 6: 109. 1966.

Holotypus: MADAGASCAR. Reg. Atsimo-Andrefana [Prov. Toliara]: Anavoha, secteur de F otadrevo poste d’Ejeda, 17.II.1960, Dauban s.n. ( P [ P00450189 ]!) .

Mat-forming annual to short-lived stoloniferous perennial, prostrate with ascending flowering culms, to 10 cm high, culms branching at every node, rooting at lower nodes, glabrous, nodes finely hirsute. Leaf sheath glabrous or sparsely pubescent with ciliate margins. Ligule a line of hairs. Leaf blade ovate, flat or sometimes folded, chartaceous, 1 – 2 × 0.05–0.4 cm, drying somewhat glaucous, glabrous on both sides. Inflorescence racemose, slender, contracted, partly exserted, 1–2 cm long. Racemes 1–2, 0.8–1.5 cm long, roughly even in length, with no secondary branching, rhachis narrowly winged, 0.5–0.8 mm wide, scaberulous, spikelets imbricate, single, subsessile, in 2 tidy rows. Spikelets elliptic, apically apiculate, 2–2.5 mm long, whiteish. Lower glume c. ¼ as long as spikelet, membranous, usually obtuse, 1–3-veined, glabrous, overlapping on opposite side of spikelet, turned towards rhachis. Upper glume as long as spikelet, membranous, 5–7-veined, with cross veins towards apex, glabrous. Lower floret infertile, palea absent. Lower lemma membranous, 5–7-veined, with cross veins towards apex, glabrous. Upper lemma obtuse, rugulose.

Distribution and ecology. – Endemic to western and southern Madagascar, with a single record from Antananarivo (Perrier 10886 locality is questioned in a note by Bosser). Open savanna and secondary vegetation on sand, spiny forest understory, disturbed areas, at elevations of 0–200m (1200 m if the Antananarivo record is correct) (F ig. 16).

Notes. – Urochloa pseudodichotoma (Bosser) Voronts. forms visually appealing spreading mats. The unusual feature of this species is dichotomous branching at each culm node, so all leaf blades are on secondary branches.

Selected specimens examined. – MADAGASCAR. Reg. Analamanga [Prov. Antananarivo]: Antananarivo-ville , I.1915, Perrier de la Bâthie 10886 ( P). Reg. Anosy [Prov. Toliara]: Atsimo-Andrefana, entre Ampanihy et Ejeda , XI.1956, Bosser 10109 ( P); Amboasary-Sud, Somangy, c. 8 km from Amboasary to Berenty , 15.III.2019, Rakotomalala et al. 268 ( K, TAN). Reg. Atsimo-Andrefana [Prov. Toliara]: near Beza Mahafaly Reserve , Ambinda stream , 15.I.1989, Phillipson & Rabesihanaka 3180 ( K, P). Reg. Boeny [Prov. Mahajanga]: près de Marovoay , V.1927, Perrier de la Bâthie 17964 ( P); Station F orestière Antsianitia , 15.II.2013, Vorontsova et al. 942 ( K, TAN). Reg. AIANA [Prov. Antsiranana]: Mahomasina , bungalows near MNP Ankarana office, 26.II.2015, Vorontsova et al. 1814 ( K, P, TAN). Reg. Sofia [Prov. Mahajanga]: nord du Bongolava, sud de Port Berge , IV.1967, Morat 2718 ( P) .