452 TETRANDRIA TETRAGYNIA. PotamogetOTt. 



1. P. indicum. R. 



Creeping. Leaves alternate, from narrow-lanceolate to 

 elliptically oval, opaque, glossy, many-nerved. Anthers 

 four pair, attached to the claws of the round concave petals. 



A native of the borders of fresh water lakes and ditches 

 in the vicinity of Calcutta. Flowers in February and March. 



Stems creeping-. The small simple roots which issue from 

 the joints are all I can discover, for while the plant advances 

 from the apex, it decays at the opposite end, so that I do not 

 think any part of them exists for one year. Branches few, 

 and like what I call the stems ; they are all round, smooth, 

 and jointed at various distances. Leaves alternate, except 

 next to the flowers, and there often opposite, petioled, from 

 narrow-lanceolate to elliptically oval, opaque, even, and very 

 smooth, or rather glossy, entire, obtuse, obscurely many- 

 nerved ; size very various. Those that remain immersed are 

 narrower, longer, more strongly marked with nerves, and 

 sub transparent. Petioles simple, not sheathing, length vari- 

 ous, in plants left by the water much shorter than the leaves. 

 Stipules solitary, axillary, sheathing, length of the petioles, 

 slit halfway or more on the inside. Peduncles solitary, axill- 

 ary, or opposite to a leaf, round, rather thicker, smooth, and 

 nearly as long as the cylindric spike, which each supports. 

 Floivers small, numerous, green. Calyx none. Petals long- 

 clawed, nearly round, incurved, fleshy; concave within, con- 

 vex on the back, permanent. Filaments none. Anthers, four 

 pairs attached to the claws of the petals on the inside. Germs 

 four, ovate-oblohg, one-celled, with one ovulum in each. 

 Styles short, and thick. Stiff mas a dark speck on the apex 

 of the styles. Drupes obovate, smooth. Nut conform to the 

 drupe, one-celled. Embryo curved, as represented by Gart- 

 ner in P. nutans, vol. ii. t. 84. 



2. P. tuberosum. R. 



Leaves alternate, and only opposite at the floriferous forks, 



