A CHECKLIST OF THE NORTH AMERICAN 

 FERNWORTS. 



(Continued.) 

 SALVIXIACEAE. 

 Azolla Lam. 



212. Azolla Caroliniana Willd. Azolla : Water 



Ferx. Not common : on the surface of still 

 water. New York, Iowa and Washington to 

 the Gulf of Mexico ; also in the tropics and 

 southward to Patagonia. 



213. Azolla filiculoides Lam. Xot uncommon ; on 



the surface of ditches and pools. California ; 

 also along the western slopes of the Andes. 



Salyixia Adans. 



214. Salvinia Natans (L.) Very rare : on the surface 



of ponds. Perry County, Missouri. Also in 

 the temperate parts of Europe and Asia. 



MARSILIACEAE. 

 Marsilia L. 



215. Marsilia quadrifolia I L ) Marsilia; Water 



Clover. Very rare ; in ponds and slow-moving 

 streams. Bantam Lake. Conn., and naturalized 

 elsewhere; also in Central Europe, and Asia to 

 Japan and Northern India. 



216. Marsilia macropoda Engelm. Xot common ; 



in water or in moist places. Texas and Xew 

 Mexico. 



217. Marsilia uncinata A. Br. Abundant on the banks 



of streams, in swamps and shallow ponds. 

 Louisiana and Texas. 



16 



