Sweet Signalgrass

This is the only species of Brachiaria occurring in China with a fertile floret which is shed from the mature spikelet. The fertile floret is also distinctive due to its smooth, glossy texture and obtuse apex.

This species and two close relatives in Africa have been placed in the separate genus Moorochloa Veldkamp.

Annual. Culms loosely tufted, slender, much branched, geniculately ascending, 30–40 cm tall, nodes softly hairy. Leaf sheaths glabrous or loosely tuberculate-hairy; leaf blades linear-lanceolate, 1.5–10.5 × 0.3–0.6 cm, glabrous or pilose; ligule ciliate. Inflorescence axis 3–6 cm; racemes 4–10, 1–3 cm, erect or narrowly ascending; rachis narrow, triquetrous, ciliate or scabrous; spikelets single, in 2 rows, overlapping. Spikelets elliptic, 1.8–3 mm, pilose, subacute; lower glume 0.2–0.3 mm, membranous, glabrous; upper glume and lower lemma as long as spikelet, 5-veined; upper floret readily deciduous, oblong, ca. 1.5 mm, thinly crustaceous, smooth, glossy, apex obtuse. Fl. and fr. summer–autumn. 2n = 18.

Loosely tufted annual; culms 10-60 cm high, slender, geniculately ascending. Leaf-blades linear to narrowly lanceolate, 2-8 cm long, 2-5 mm wide, glabrous or pubescent. Inflorescence of 3-12 racemes on an axis 1-6 cm long; racemes 0.5-2.5 cm long, secund, bearing single spikelets imbricate on a triquetrous rhachis. Spikelets elliptic, 1.7-2.7 mm long, pubescent (rarely glabrous or villous), sub-acute; lower glume a minute scale 0.2-0.5 mm long (up to a fifth the length of the spikelet); upper lemma readily deciduous, smooth, shiny, obtuse.

Distribution: Pakistan (Sind, Baluchistan, Punjab, N.W.F.P. & Kashmir); South Africa to the Mediterranean; eastwards to India.

Fl. & Fr. Per.: July-September.

Open and disturbed situations on hill slopes and in dry fields as an arable weed. Fujian, Guizhou, Yunnan [India, Malaysia, Thailand; N Africa, Mediterranean region].

Panicum eruciforme Smith in Sibthorp & Smith, Fl. Graeca 1: 44, t. 59. 1806; Brachiaria isachne (Roth ex Roemer & Schultes) Stapf; Echinochloa eruciformis (Smith) Koch; Moorochloa eruciformis (Smith) Veldkamp; P. caucasicum Trinius; P. isachne Roth ex Roemer & Schultes.