IOWA ACADEMY OF SCIENCES. 219 



ULMACE^. 



Ulmus L. 



205. U. americana L. White or Water Elm. Common 



along streams; one of our most desirable shade 

 trees. 



206. U. fiilva Michx. Slippery Elm. Frequent. 

 Celtis L. 



207. C. occidcntalis L. Hackberr}'. Kather rare. 



MORACE^. 



Cannabis L. 



208. C. sativa L. Hemp. A native of Europe and Asia, 



escaped from cultivation. 



urticace^. 

 Urtica L. 



■ 209. U. gracilis Ait. Nettle. Common in woods, and 

 introduced into rich ground near dwellings, 

 where it is a troublesome weed. 

 Urticastrum Fabr. 



210. U. divaricatum (L) Kuntze. (Laportea canadensis 



Gaud.) Common in woods. 

 Adicea Raf. 



211. A. pnmila (L.) Raf. (Pilea pnmila Gray.) Com- 



mon in low woods. 

 Parietaria L. 



212. F. potnsj/Ivanica Muhl. Infrequent, south shore 



of Iowa Lake. 



SANTALACE^. 



Comandra Nutt. 



213. C. mnhellata (L.) Nutt. Common on prairies. 



ARISTOLOCHIACE^. 

 ASARUM L. 



214. .1. canadense L, Wild Ginger. Rare in woods west 



of Estherville. 



