拟纤细茨藻 ni xian xi ci zao

Stems ca. 10 cm tall, ca. 0.3 mm in diam. Leaves often in pseudowhorls of 5, 9-11 × ca. 0.3 mm; sheath 1-2 mm; auricles orbicular to slightly obcordate, short, minutely serrulate with 3-5 teeth, upper margin on each side minutely serrulate with 6-10 teeth. Plants monoecious; flowers 1-3 per axil, male flowers in upper axils and female ones below. Male flowers elliptic, 0.6-0.8 mm; spathe absent; anther 1-thecous. Female flowers inconspicuous, ca. 1 mm; style ca. 1 mm; stigmas 2- or 3-lobed. Fruit 1.6-2 × ca. 0.5 mm. Seeds elliptic-oblong, with more than 25 rows of pits; areoles oblong, longitudinally elongated; cell walls not raised. Fl. and fr. Jul-Nov.

● Known only from ponds on Chung Chi Campus, Hong Kong.

Najas pseudogracillima is most similar to N. gracillima, especially in vegetative condition. It differs by having male flowers without a spathe, whereas N. gracillima has male flowers with a spathe.