IOWA ACADEMY OF SCIENCES. 217 



184. C. /nrsKt/nii Mill. (('. puhrscens Willd.) Large 



Yellow Lady-slipper. Rare in woods west of 

 Estherville. 

 H ABENAKI A AVilld. Reiii Orchis. 



185. //. leacophn'ft (Nutt.) A. Gray. Frequent on low 



prairies. 

 Oyrostach^s Pers. 



1S(). G. ccrnua (L.) Kuntze. (Spirrmthes cernua L. C. 



llicliards.) Very rare on low prairies. 

 Leptorchis Thouars. 



187. L. Iwselil (L.) Mac M. {L'qxiris heselii L. C. 



Richards.) Very rare; artificial grove, one and 

 one-half miles northeast of Armstrong, where 

 it w^as probably introduced by the birds. It is 

 not known from any other locality in the state. 



JUGLANDACE^. 

 JUGLANS L. 



188. J. jiirjra L. Black Walnut. This valuable tree 



once quite common along streams, is becoming 

 rare. 

 HicoRiA Raf. 



18y. 11. iiiinima (Marsh.) Britton. {Can/a amara Nutt.) 

 Bitter-nut. Frequent in woods; our only 

 hickory. 



SALICACE.-E. 

 POPULUS L. 



190. P. alba L, White or Silver-leaf Poplar. Escaped 



from cultivation; the tree, although a hand- 

 some one, can not be recommended, as it 

 spreads badly by the roots. 



191. P. fremuloides Michx. American Aspen. Infre- 



quent in woods; rarely in clumps on the 

 prairie. 



192. P. deltoldes Marsh. (P. uionilifeni Ait.) Cotton- 



wood. Rare in the native state in several 

 localities in the county, but becoming very 

 common in cultivation and as an escape in low 

 ground. 



