长稃伪针茅 chang fu wei zhen mao

Pseudoraphis longipaleacea L. C. Chia.

Perennial, with rhizomes. Culms slender, floating, 20–70 cm long when flowering, smooth, nodes glabrous. Leaf sheaths loose, keeled, glabrous, mouth with lanceolate auricles adnate to the ligule; leaf blades linear, soft, 3–5 × 0.2–0.4 cm, abaxial surface smooth, adaxial surface scabrous, base rounded, apex subacute; ligule membranous, white, glabrous, subtruncate. Inflorescence linear, 4–5 cm, composed of few spikelets; racemes erect, alternate, bearing a single spikelet (rarely 2), terminal bristle 8–24 mm. Spikelets 4.5–6.5 mm, acute; lower glume 0.5–0.7 mm, obtuse or subtruncate; upper glume as long as or slightly shorter than lower lemma, glabrous, 7–9-veined, acute; lower lemma equal to spikelet, 13-veined; anthers 3, ca. 3 mm; upper lemma ca. 2.5 mm. Fl. and fr. Sep–Oct.

Ponds, lakes. Hainan [Thailand, Vietnam].

Pseudoraphis balansae is distinctive in the genus because its spikelets are merely acute, lacking the drawn-out, narrow tip on the upper glume found in most species. The short, subacute leaves, white, truncate ligule, and few-spiculate inflorescence are also characteristic.