Flora of Denver. 47 



380. .Euphorbia hexagona NUTT. Found by T. C. 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/E. (Nettle Family.) 



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

 very common. 



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

 Common. 



CUPULJFERjE. (Oak Family.) Btwaoft Lfl: 



388. Betula occidentalis HOOK. Along the Platte near 

 Denver. Coulter. 



389. Alnus vfridis AIT. Along the Platte near Valverde. 



SALICINEjE. (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- 



