Halophila stipulacea Asch.

Dioecious.. Roots 1 per node.. Rhizome narrowly terete, unbranched, 0.2–2 mm. in diameter, whitish or greenish.. Erect stems narrowly terete, up to 1.5 mm. long, 0.2–0.5 mm. wide.. Leaves in pairs, 1 pair on each erect stem; blade linear to oblong or linear-elliptic, 1.5–8 cm. long, 2–6 mm. wide, often slightly falcate, obtuse or rounded at apex, cuneate at base, glabrous, somewhat translucent, light to mid-green, rarely dark green, with 2 of the longitudinal veins running just below the margin, connected by numerous pairs of somewhat inconspicuous cross-veins ascending at an angle of 40–60°; margins green, serrate at least near the apex; petiole 0.4–1.5 cm. long.. Stipules obovate, 8–17 mm. long, 4.2–10 mm. wide, notched, strongly keeled, glabrous, greenish or whitish.. Male flowers not seen.. Female flowers: spathe-bracts ovate, ± 10 mm. long, ± 0.7 mm. wide, emarginate, keeled, the keel denticulate, whitish, translucent; ovary of 3 carpels, ovate or ovate-elliptic, 2–3 mm. long, perianth-tube up to 6 mm. long, the lower portion persisting as beak in fruit; styles 3; stigmas 3, 20–25 mm. long.. Fruit ellipsoid, ± 5 mm. long, ± 2 mm. wide, with beak up to 6 mm. long, whitish or brown.. Seeds up to 40, subglobose, 0.5–0.6 mm. long, ± 0.5 mm. wide, reticulate, light brown.

Preferring localities which are always submerged and subjected to a constant current.