Class IV. Order IV. 63 



lobed stigma in the perfect ones ; the shrub being strictly poly- 

 gamous. Berries deep red. Swamps, Cambridge. May. 



68. POTAMOGETON. 



POTAMOGETON NATANS. L. Floating Pond weed. 



Upper leaves oblong-ovate, rounded at the base, 

 petioled, floating. Sm. 



A very common species of pond weed, growing near the mud- 

 dy banks of deep waters. Leaves oblong, sometimes a little 

 hearted at base, two inches long, floating on the surface, on foot- 

 stalks accommodated to the depth of the water. In June the 

 spikes of dull flowers emerge on solitary round footstalks, sur- 

 rounded at base by lanceolate bractes or stipulae. 



POTAMOGETON FLUITANS. L. Long leaved Pond iveed. 



Leaves petioled, lower ones linear, very long, up- 

 per ones lanceolate, nerved, coriaceous. 



Leaves narrower than the preceding, the immersed ones very 

 long and linear. Ponds. June. 



POTAMOGETON PERFOLIATUM. L. PerfoUate Pond weed. 

 Leaves cordate-ovate, clasping, all immersed ; 

 spikes terminal ; flowers alternate. 



This has no floating leaves, the flowers only appearing above 

 water. July. 

 POTAMOGETON LUCENS. MX. Shining Pond tveed. 



Leaves lanceolate, subsessile with a thick midrib ; 

 spikes long, cylindrical. 



A very long, large leaved species. Leaves immersed. Ditch- 

 es, &c. July. 

 POTAMOGETON SETACEUM. ll'illd. Setaceous Pond weed. 



Upper leaves opposite, lanceolate, five nerved, on 

 short petioles ; lower ones alternate, filiform ; spikes 

 dense, shorter than the leaves. 



Very different in size from any of the preceding, the wholr 

 plant being small and slender. July. 



i 



