澳古茨藻 ao gu ci zao

Caulinia oguraensis (Miki) Nakai.

Stems 20-30 cm tall, 1-2.5 mm in diam. Leaves narrowly linear to subulate, 1-2 cm × 1-3 mm, slightly curved; midvein sometimes with spines; sheath 3-5 mm; auricles orbicular to obcordate, short, minutely serrulate with several teeth at apex; leaf margin serrulate with 7-14 teeth on each side. Plants monoecious; flowers solitary, male flowers usually in upper axils, female ones throughout. Male flowers elliptic, ca. 1 mm; spathe with a neck, with several brownish spine cells at apex; anther 4-thecous. Female flowers ca. 3 mm; style ca. 0.5 mm; stigmas 2-lobed. Fruit narrowly ellipsoid, 3-4 × ca. 1 mm, narrowed and curved at apex. Seeds narrowly ellipsoid, with many rows of transversely elongated ladderlike pits; areoles hexangular. Fl. and fr. Jul-Nov. 2n = 24, 60*.

Still water. Hubei, Jiangxi, Taiwan [India, Japan, Korea, Nepal, Pakistan].