三头水蜈蚣 san tou shui wu gong

Kyllinga nana Nees.

Perennials. Rhizomes short. Culms tufted, 5-30 cm tall, compressed 3-angled, smooth, base swollen, bulbous, and clothed with persistent brown leaf sheath remains splitting into fibers. Leaves shorter than culm; leaf blade 2-3 mm wide, flaccid, folded or flat, apical margin sparsely denticulate. Involucral bracts 2 or 3, leaflike, longer than inflorescence, ± horizontal, downward reflexed after anthesis. Spikes usually 3, with numerous spikelets congested into a capitate shape; middle spike broadly ovoid, 5-6 mm; lateral spikes globose, 3-4 mm. Spikelets radially arranged, oblong, 2-2.5 mm, 1-flowered. Glumes greenish yellow and reddish brown maculate, ovate to ovate-ellipsoid, 2-2.5 mm, concave, keel abaxially green, veins 2 or 3 on each side of keel, apex mucronate. Stamens 1-3. Style short; stigmas 2, longer than style. Nutlet yellowish brown, oblong, 2/3-3/4 as long as subtending glume, compressed plano-convex, with punctate processes. Fl. and fr. Jul-Oct. 2n = 14.

Wet places at field margins. Guangdong, Hainan [Bangladesh, India, Malaysia (Peninsular), Myanmar, Pakistan, Sri Lanka, Thailand, Vietnam; tropical Africa].

Kyllinga bulbosa is naturalized in E Australia and Malaysia.

The name Kyllinga triceps Rottbøll (Descr. Icon. Rar. Pl. 14. 1773) has been misapplied to this species (e.g., in FRPS 11: 185. 1961). That name was nomenclaturally superfluous when published and is therefore illegitimate because, in the protologue, Rottbøll cited the older name Scirpus glomeratus Linnaeus (Sp. Pl. 1: 52. 1753) as a synonym.