Class. XX.— DiOECIA. 



Order II.— DIANDRIA. 



^9. VALISNERIA. MchelL L, 



Masc. 'Spathe ovate, 2-parted. Spadix co- 

 vere«l with minute flowers. Calix S-parled. Fem. 

 Spaihe bifuj, 1 flowered. Calix S-parted, su- 

 peiior. Corolla of 3 petals. Stigmas 3, iigu- 

 late, semibifid. Ctt;?s?//(J valvelcss, l-celled, seeds 

 numerous, paiietally attached. (Stamina 2 

 and 6.) 



Submersed aquatics; leaves all radical; scapes axlllar)'. 

 Female flowers solitary, mostly fiirnislitd with a spiral 

 ' filiform scap^-, stretcliing or contracting (as in Jiuppia and 

 * Udora') in order to admit tlie en;ersion of the flower; 

 male scape very short, and always submersed, the minute 

 florets scarcely (larger than tlic anthers of the Rose) at 

 length breaking connexion with the parent plant, rise to 

 the surface, and instantly expanding to the light, acciden- 

 tally float around the other sex and quickly perish; the 

 period of infiorescence passed, the female at length sinks 

 beneath the water and matures the fruit. 



Species. 1. V. americcma. Leaves linear and obtuse, 

 equal from the base, 3-nerved, margin minutely and acu- 

 leately serrulate; male peduncles very short, female ones 

 spiral. — Apparently a mere variety of V. spiralis. Male 

 flowers very minute, o-valved, valves concave; stamina 1 

 or 2. Hab. Common in still water, on the margins of 

 rivers from New York to Florida, also in Lake Michigan, 

 and probably throughout the Illinois territory. 



Of this singular genus, which ought probably to be di 

 ^vlded, there is 1 species in Europe, and 2 in India. 



80.' SALIX. L, (Willow.) 



Masc. ^iment cylindric. Calix consisting of 



