Brachiaria fruticulosa A. Camus

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 : 212

7. Brachiaria fruticulosa A. Camus in Bull. Mus. Natl. Hist. Nat., sér. 2, 29: 276. 1957.

Lectotypus (designated here): MADAGASCAR. Reg. Anosy [Prov. Toliara]: Mont Ankazovandamena, près de la Baie des Galions (Ronofotsy) au SW de F ort-Dauphin, 100 –450 m, 21.II.1955, Humbert & Capuron 29066 ( P [ P02344007 ]!; isolecto-: P [ P02344004 , P02344009 ]!) .

Loosely tufted perennial, scrambling or erect, to 2 m high, culms woody, branched, resembling a bamboo, glabrous. Leaf sheath glabrous or hirsute with ciliate margins. Ligule a truncate membrane, with a tissue rim and a line of cilia outside of leaf. Leaf blade narrow-lanceolate, chartaceous, 2–7 × 0.3– 0.7 cm, glabrous on both sides. Inflorescence racemose, slender, open, difficult to see among branches, 5–8 cm long. Racemes 2–4, 1–5 cm long, decreasing in length upwards, on a common axis 1– 5 cm long, with no secondary branching, rhachis narrow, smooth or minutely scaberulous, spikelets not overlapping with adjacent spikelets, single or paired, on pedicels of uneven length. Spikelets elliptic, apically obtuse, 2.5–2.8 mm long, whiteish. Lower glume ⅓ as long as spikelet, membranous, obtuse, 3-veined, scaberulous towards apex, with hyaline margins, the orientation relative to rhachis variable. Upper glume as long as spikelet, membranous, 5-veined, scaberulous towards apex, with an apical crest. Lower floret infertile, palea absent. Lower lemma chartaceous, 5-veined, scaberulous. Upper lemma acute, smooth with minute trichomes towards apex, shiny, pale, with a green apical crest.

Distribution and ecology. – Known from the type only, southeastern Madagascar, seasonal forest shade on gneiss, at elevations of 100–450 m (F ig. 5) .

Notes. – This mysterious species does not seem to have been seen again after the sole collection event in 1955. While the inflorescences have some superficial resemblance to the Malagasy highland endemic Panicum andringitremse A. Camus , the hard woody knotted rootstock, and the bamboo-like branching structure do not bear clear resemblance to any other species. No original field notes are available but the specimens suggest a small bamboo-like habit, partly erect and partly scrambling in shade over rocks, perhaps similarly to Oldeania ibityensis (A. Camus) D.Z. Li et al. Without the availability of DNA sequences it is difficult to be confident of its origins and taxonomic placement. The spikelet structure marks it clearly as a member of the tribe Paniceae , most likely the Boivinellinae, perhaps affiliated with the other bamboo-like scramblers in the genus Pseudolasiacis (A. Camus) A. Camus, although Pseudolasiacis are larger plants with bigger leaf blades and inflorescences, known from higher elevation habitats.

The lectotype designated here [ P02344007 ] has the best preserved material and is annotated by Camus .