18. Eleocharis congesta D. Don, Prodr. Fl. Nepal. 41. 1825.
密花荸荠 mi hua bi qi
Eleocharis purpurascens Boeckeler.
Perennials. Rhizomes decumbent. Culms tufted, 10-40 cm tall, 1-1.5 mm thick, slightly firm, subterete, with several longitudinal thin ribs. Leaf sheaths 2; cauline sheaths blood-red but later becoming pale blood-red apically, 3-8 cm, mouth truncate, apex mucronate to aristate. Spikelet oblong to narrowly oblong-ovoid, 8-11 × 3-4 mm, densely many flowered, sometimes proliferous at spikelet base, apex obtuse to acute. Basalmost glume empty, amplexicaul for whole spikelet base; fertile glumes blood-red but green medially, tightly imbricate, oblong, ca. 2.2 × 0.9 mm, margin very narrowly hyaline, apex subrounded. Perianth bristles 6, longer than nutlet, slightly densely and shortly retrorsely spinulose. Stigmas 3. Nutlet yellowish to olivaceous, obovoid to ellipsoid, ca. 1 × 0.7 mm, 3-sided, sides convex, angles narrowly costate; persistent style base white, half-oblong, 1/4-1/3 as long and ca. 1/2 as wide as nutlet, spongy initially but hardened when dry, base cap-shaped, apex rounded but becoming pyramidal and acute when dry. Fl. and fr. May-Aug.
Forest margins, pond margins, river margins; 1300-1400 m. Yunnan [Bhutan, India, Indonesia, Japan (Ryukyu Islands), Kashmir, Malaysia, Myanmar, Nepal, Pakistan, Philippines, Sri Lanka, Thailand, Vietnam; Pacific islands].