Arundo formosana Hack.

Occasional in dry grassland as well as on rocky cliffs.

The culms are used for basket making.

Perrenial, tufted with short rhizome. Culm pendent, about 2-6 mm in diameter. Blades 10-12 mm wide, basal parts covered with long silky hairs; ligule 0.5 mm long, fimbriate on upper margin, hipid on dorsal side; sheath usually longer than the internode, tightly clothing the culm, glabrous Panicle open, 10-30 cm long. Spikelets 2-5-flowered, about 6 mm long. Glumes subcoriaceous, siliceous, 3-nerved, rarely 4-nerved; the lower glume about 3 mm long, apex acute, the uppe glume about 4 mm long, apex gradually narrowed; lemma about 3 mm long, 5-nerved, apex with a 2 mm long awn, basal part silky hairy which are nearly as long as the lemma; palea about 2.5 mm long, 2-keeled, the margins hispid, apex with a sinus; lodicules 2, truncate, conspicuously nerved, stamens 3. anther 1.5 mm long.

Tufted perennial from a short rhizome. Culms relatively slender, suberect to pendant, 0.6–1.2 m tall, 2–6 mm in diam., with slender clusters of branches from nodes. Leaf sheaths longer than internodes, glabrous; leaf blades 10–25 × 0.5–1.5 cm, margins scabrous, basal part with long silky hairs, apex acuminate; ligule 0.5–1 mm. Panicle 10–30 cm, loosely contracted, light brownish; branches 5–8 cm, ascending. Spikelets 6–10 mm, florets 2–5, uppermost floret much reduced; glumes 3–4 mm, 3-veined, lower glume lanceolate-elliptic, acuminate, upper glume lanceolate, acuminate; lemmas narrowly lanceolate, 3.5–6 mm, 5-veined, dorsal hairs 1.5–3 mm, apex subentire to minutely bidentate with 1.5–3 mm awn from sinus, lateral veins shortly extended or not; palea 2/3 length of lemma body. Fl. and fr. Jun–Dec.

Ryukyus, Taiwan and Philippine.

Dry coastal grassland and sea cliffs. Taiwan [Japan (Iriomote Island in S Ryukyu Islands), Philippines].

Arundo formosana var. gracilis Hackel; A. formosana var. robusta Conert; A. parviflora Ohwi.