Ischaemum aureum (Hook. & Arn.) Hack.

No Taiwan specimens have been deposited in Taiwan herbaria.

This is a very locally distributed grass, with yellowish-hairy racemes and contrasting, reddish brown stigmas. The pedicelled spikelets are usually bisexual, exserting their stigmas and maturing before the sessile spikelets, but otherwise the species is typical of the genus Ischaemum.

Culm 20-30 cm tall, about 1 mm in diameter. Blade about 5 cm long by 4 mm wide; ligule chartaceous, about 1 mm long, truncate, hispid on the back. Inflorescence of 2 racemes. Spikelets paired, more or less similar; rachis-joint and pedicel thickened and swollen, about 7 mm long; lower glume coriaceous, lanceolate, 2-keeled, ciliate along keels, irregularly 2-toothed, inconspicuously several-nerved, upper margin fimbriate, shortly 2-toothed, aristate. Lower floret lanceolate, chartaceous, about 5 mm long, lemma and palea fimbriate along margins; lemma 1-nerved; palea 2-keeled. Upper floret about 4 mm long, hyaline; lemma 2-cleft, fimbriate, 3-nerved, with a stout flexuous awn of about 18 mm long, arising from the sinus; palea toothed, about 2.5 mm long. Caryopsis elliptical, about 1.5 mm long; embryo 1/2 the length of the caryopsis.

Perennial from short rhizome. Culms loosely tufted, 20–30 cm tall, internodes short and leaves crowded in lower part, nodes glabrous. Leaf sheaths smooth, glabrous; leaf blades broadly linear, 3–12 × 0.3–0.8 cm, smooth, glabrous or a few setae on adaxial surface above ligule, base contracted, apex acuminate; ligule ca. 1 mm, truncate. Racemes terminal, paired, erect but usually separate, 2–5 cm, yellowish hairy; rachis internodes oblong-clavate, triquetrous, outer angle densely ciliate with long yellowish hairs, inner angles shortly ciliate or glabrous. Sessile spikelet lanceolate, 4–5 × ca. 1 mm, yellowish; lower glume subleathery in lower part, 2-keeled, wingless, keels thickened, ciliolate, also pilose with ca. 2 mm yellow hairs, sometimes sparsely or ciliolate throughout, papery and asperulous toward apex with obvious anastomosing veins, apex bicuspidate; upper glume pilose on upper keel, apex 2-toothed, 2–3 mm awn from between teeth; awn of upper lemma 1.8–2.5 cm. Pedicelled spikelet ± equaling sessile, usually bisexual, slightly laterally compressed, both glumes 1-keeled, shortly awned, upper lemma awned.

Distributed on littoral regions of the Ryukyus and Taiwan.

Coral rocks and bluffs of the seashore. Taiwan [Japan (Ryukyu Islands)].

Spodiopogon aureus Hook, & Arn., Bot. Beech. Voy. 273. 1840.

Spodiopogon aureus Hooker & Arnott, Bot. Beechey Voy. 273. 1838.