Najas graminea var. graminea Poll.

Up to 50(-75) cm, lower internodes 1-10 cm, by (0.6-)0.7-1.5 mm. Leaves (1¾-)2.5-3.5(-4) cm by (0.6-)0.7-l(-1.4) mm, flat, rarely canaliculate; apex obtuse (-rounded), rarely somewhat acute (blade c. 3 mm below the tip 0.4-1 mm wide); margin on either side with (40-)60(-100) spiny teeth; midrib c. 0.07-0.05 times as wide as the blade; cavities narrow, occupying up to 1/4 of the blade; septa indistinct. Sheaths (3-)4-5(-6) by (2-)3-4(-5) mm, on either side with (10-)15-20 (-30) spiny teeth; 3-8 teeth on the inner edge of the auricle; auricles about straight, (1-)2(-2.6) by 0.5-1 mm, entire, rarely shallowly lobed. Flowers often up to 3 together, in different stages, together with a male, or male solitary. Male flowers: anther 4(-2)-celled, elliptical, rarely ovate or oblong, (1-)1.5(-2) by (0.4-)0.7(-1) mm;'perianth lobes' distinct, rounded to globular; 'pedicel' 0.2-0.5 mm, at anthesis 1-2.5 mm. Female flowers (1.6-)2(-2.5) mm; ovary (0.6-)0.7(-1) by (0.2-)0.35 (-0.4) mm; style (0.4-)0.7(-1.2) mm, with 2(-3) stigmas (0.4-)0.8(-1.6) mm. Seeds (1.6-, broad seeds) 2.3(-2.7) by (0.6-, long seeds) 0.8(-0.9) mm; testa with 20-34 length-rows of 30-45 subquadrate to 5-6-angular areoles (often slightly higher than broad).

Chiefly in the lowland in rice-fields, ditches, small streams, inbotheverwetand seasonal areas, up to 400 m, rarely at 1000 m (W. Java), once at 1400 m (Wetar), often together with Nitella, Salvinia, Mars ilea, Pistia, and other aquatics. By BRANDIS noted to occur in a hot spring in Burma at 92° F.