HYDROPTERIDES. 341 



The plants from these several localities do not differ from each 

 other in any essential respect. The leaves and peduncles, in speci- 

 mens from the same locality, sometimes vary in being more or less 

 villous. Our Oregon plant is evidently the M. vestita of Hooker and 

 Greville, although not quite so hairy in all its parts as represented 

 by their figure. It is very possible that the M. hirsuta of R. Brown 

 may be identical with the present species, but we have not the means 

 of determining this point. 



3. Marsilea polycarpa, Hook. & Grev. 



Marsilea polycarpa, Hook. & Grev. Ic. Fil. t. 160. 



Hab. Tahiti, Society Islands ; at Papeiti and Point Venus : in slow 

 moving waters. 



It is gratifying to be able to extend the geographical range of this 

 interesting and beautiful species, which, so far as we know, had been 

 found only in the tropical parts of South America. 



2. SALVINIA, Michx. 

 1. Salvinia rotundifolia, Willd. 



Salvinia rotundifolia, Willd. Spec. PI. 5, p. 537; Raddi, Plant. Brasil. 1, p. 1, t. 1, 

 f. 5 ; Gaud. Bot. Freyc. Voy. p. 406. 



Hab. Floating in the Rio Anhumirim, Estrella, Brazil. 

 2. Salvinia biloba, Raddi. 



Salvinia biloba, Raddi, Plant. Brasil. 1, p. 1, t. 1, f. 4, a, b. 

 Marsilea natans, Velloz. Fl. Flum. 11, t. 111. 



Hab. Floating in the Rio Anhumirim, Estrella, Brazil ; in great 

 abundance. 



"Very distinct from the preceding species in its two-lobed leaves. 



