YYHEDS OF MONTANA. 



63 



and can be exterminated only by cultivation or by digging; the 

 latter is most effective when the roots are cut off just below the 

 crown of leaves during the flowering season. Apparently well dis- 

 tributed in the state about towns. [Fig. 19.] 



125. *THLASPI ARVENSE, L. Pennycress. 



An introduced annual of the Mustard family much resembling 

 the birdseed (Lepidium apetalum) but having larger pods. Oc- 

 casional in grain fields and waste places. 



126. *TRAGOPOGON PORRIFOLIUS, L. Salsify; Oyster-plant. 



In gardens and waste places; not infrequently escaped from 

 cultivation. 



127. *URTICA DIOICA, L. 



Fig. 20. Urtica gracilis, Ait. 

 *4 natural size. 



Branch 



A perennial nettle about barn- 

 yards and in waste places in the 

 Koutenai region. Infrequent. Ap- 

 parently here, coming in from 

 the west. 



128. URTICA GRACILIS, Ait. 



Stinging Nettle. 



A tall slender unbranched per- 

 ennial with green fruit clusters 

 in the axils of the upper leaves, 

 and with stinging hairs. Not in- 

 frequent in streets and waste 

 places and along highways in 

 the region east of the Divide, but 

 sparsely introduced westward. 

 Usually regarded as native, but 

 in this state its habit is wholly 

 that of an introduced species and 

 occurs only where its seeds may 

 have been transported in hay, 

 water or mud from points of 

 settlement. [Fig. 20.] 



