3. Machaerina rubiginosa (Solander ex G. Forster) T. Koyama, Bot. Mag. (Tokyo). 69: 65. 1956.
圆叶剑叶莎 yuan ye jian ye suo
Schoenus rubiginosus Solander ex G. Forster, Fl. Ins. Austr. 89. 1786; Fuirena rubiginosa (Solander ex G. Forster) Sprengel.
Rhizomes long, horizontal, scaly. Culms tufted, (0.3-)1-1.8 m tall, 2-6 mm thick, compressed biconvex to subterete, smooth. Basal leaves shorter than to equaling culm; leaf blade erect, (2-)4-7 mm wide, biconvex with obtuse edges to subterete, smooth; pith spongy. Cauline leaves long sheathing with short blades. Inflorescences paniculate, erect, narrow, dense or interrupted, (10-)20-50 cm, 3-7-noded. Spikelets in oblong to globose clusters, 4-7 × 2-2.5 mm, narrowly ovoid maturing to ovoid, 2- or 3-flowered, bearing 1 or 2 nutlets. Glumes 5, ovate to lanceolate, 4.5-6.5 mm, margins long ciliate, apex acuminate. Perianth bristles absent. Stamens 3; anthers 1.5-2 mm; connective apex prominently apiculate. Nutlet orange to reddish brown, sessile, ellipsoid to oblong-ellipsoid, 3-5 × 1.5-2 mm, 3-sided, smooth, shiny; persistent style base depressed to shortly pyramidal, densely hairy. Fl. and fr. Apr-Aug.
Swamps, lake margins, Sphagnum bogs; below 1800 m. Hong Kong, Yunnan (Tengchong) [Bangladesh, India, Indonesia, Japan (Ryukyu Islands), Malaysia, Papua New Guinea, Philippines, Sri Lanka, Vietnam; Australia, Pacific islands (New Zealand)].