Potamogeton. tetrandria tetragynia. 453 



sessile, linear, much waved, entire, clear, when dry membra- 

 naceous. 



Found immersed in extensive masses, in ponds, lakes, and 

 receptacles of fresh water in Bengal, during the dry season, 

 chiefly when in flower in February, it rises so near to the sur- 

 face as to allow the little spikes of flowers to emerge com- 

 pletely. 



Root of long simple fibres, brown, &c. according- to the 

 colour of the mud they enter ; on the creeping joints are ge- 

 nerally found small roundish lobate, viviparous tubers. Stems 

 and branches of various lengths, according to the depth of the 

 water, &c. a groove on each side gives them the appearance 

 of being compressed, thick as a pack thread, smooth, at the 

 bottom of the water creeping, towards the extremities when 

 in flower dichotomous ; previously to that period the branches 

 are alternate and axillary. Leaves sessile, alternate, except 

 at the floriferous fork of the branches, where they are oppo- 

 site, linear, rather obtuse, much waved, finely and acuteiy 

 serrulate, with two slender nerves near the margin, pellucid, 

 from two to three inches loug, by little more than a quarter 

 of an inch broad. Stipules sheathing, short, smooth, greenish 

 like the other parts of the plant, and scarcely to be distin- 

 guished from them. Spikes solitary in the fork of the 

 branches, rather long-peduncled, from four to eight-flowered, 

 when in blossom emerged, afterwards immerged. Corol, 

 stamina, and germ as in the genus, but here there certainly is 

 a style with four large, obliquely truncated stigmas. Seed as 

 in P. nutans, Gcert. sem. ii. 23. tab. 84. 



c « 3 



