Flora of Denver. 47 



380. Euphorbia hexagona NUTT. Found by T. G. Porter 

 near Denver. 



381. Euphorbia marginata PURSH. (SNOW-ON-THE-MOUN- 

 TAIN, MARGINED-SPURGE). Leaves usually white margined, 

 markings variable. Common on the plains. Summer to fall. 



382. Euphorbia dentata MICHX. Tall . and erect, leaves 

 often blotched with purplish red.- Common in the late sum- 

 mer and fall. 



383. Euphorbia dictyosperma FISCH. AND MEYER. An- 

 nual, pod warty, seeds veined. Along the Platte. Summer. 



384. Euphorbia montana ENGELM. Pod smooth, seeds 

 dotted, very leafy. Common along the Platte. 



CALLITRICHACE^E. 



385. Callltriche verna L. In stagnant water, near Val- 

 verde. 



URTICACE^. (Nettle Family.) 



386. Urtica gracilis AIT. (NETTLE.) Along streams, not 

 very common. 



387. Humulus Lupulus L. (HOP-VINE.) Along the Platte. 

 Common. 



CUPULl'FER^. (Oak Family.) 



388. Betula occidentals HOOK. Along the Platte near 

 Denver. Coulter. 



389. A"lnus viridis AIT. Along the Platte near Valverde. 



SALICINE/E. (Willow Family.) 



390. Salix amygdaloides ANDERS. Leaves narrowed to a 

 very fine point, glaucous beneath, serrate, catkins on leafy pe- 

 duncles. Along the Platte. North Denver. Common- 



