Pseudoraphis brunoniana (Griff.) Pilg.

This species is closely related to Pseudoraphis spinescens (R. Brown) Vickery, with which it has often been confused. Pseudoraphis spinescens has a widespread distribution from India and Sri Lanka through Malaysia and Indonesia to Australia. It differs in its densely hairy nodes with shiny, white, appressed, silky hairs; longer racemes bearing 5–10 approximate spikelets, usually with a shorter terminal bristle; and by its caudate upper glume much exceeding the lower lemma.

Culms soft, compressed, usually floating, emergent flowering shoots 20–40 cm, nodes pubescent. Leaf sheaths usually longer than internodes, mouth with lanceolate auricles adnate to the ligule; leaf blades linear-lanceolate, 3–9 × 0.3–0.6 cm, base contracted, apex acute; ligule membranous, lacerate, ciliolate. Inflorescence open, lanceolate to ovate in outline, 5–10 cm; racemes stiff, ascending to patent, bearing (1–)2–3 distant spikelets on a slender scabrous rachis, terminal bristle (7–)15–30 mm. Spikelets 5.5–8(–10) mm; lower glume 0.5–1 mm, broadly rounded or truncate; upper glume lanceolate, as long as spikelet, 7–11-veined, sparsely spinulose on veins and margins, apex slenderly acuminate; lower lemma slightly shorter than upper glume, 7–9-veined; anthers 3, 1.3–2 mm; upper lemma ca. 2 mm. Fl. and fr. Jul–Aug.

Rooting in shallow water, floating in deep water. Anhui, Guangdong, Taiwan [Bangladesh, NE India, Myanmar, Philippines, Thailand, Vietnam].

Panicum brunonianum Wallich & Griffith, J. Asiat. Soc. Bengal 5: 574. 1836; Chamaeraphis brunoniana (Wallich & Griffith) A. Camus; C. spinescens (R. Brown) Poiret var. brunoniana (Wallich & Griffith) J. D. Hooker.