丝粉藻 si fen zao

Phucagrostis rotundata (Ascherson & Schweinfurth) Ehrenberg & Hemprich.

Creeping rhizomes slender, each node with 1-3 roots and 1 short erect shoot. Leaves 2-5 together on shoots, ± falcate, 7-15 cm × ca. 4 mm, 9-15-veined, with secondary veins between lateral veins, sometimes slightly dentate toward apex, apex rounded to truncate; sheaths 1.4-4 cm. Anthers ca. 1.1 cm. Carpel ca. 5 mm along with slender styles. Fruitlet semicircular, ca. 1 cm, abaxially with 3 parallel ridges, middle ridge 6-8-toothed.

Marine shallow sandy bottoms. S Hainan (Sanya) [India, Indonesia (Java), Malaysia, Myanmar, Philippines, Thailand, Vietnam; Africa, Australia; W Pacific Ocean and Indian Ocean to Red Sea].