伪针茅 wei zhen mao

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.

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].

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.