282 



IRTICACEAE 



3. Papyrius Lam. (Broussonetia L'Her.) 

 P. papyrifera (L.) Kuntze. Along roadsides: N. Y. to Fla. 

 and Mo. Native of Asia. 



Rare in our range as a localized escape. 



CANNABINACEAE 



Twining vines. 

 Erect herbs. 



4. Humulus L. 



Bracts and achenes dotted with yellow, resinous grains. 

 Bracts and achenes not so dotted. 



1. Humulus. 



2. Cannabis. 



1. H. Lupulus. 



2. H. japonicus. 



H. Lupulus L. In thickets and on river banks: N. S. to Man., 



N. Y. and Pa., in the Alleghanies to Ga. and Kan., and in the 



Rocky Mts. to Ariz, and N. Mex. Also in Europe and Asia. 



Throughout the range, except in southern N. J.; often an escape 



from cultivation. 



2. H. japonicus Sieb. and Zucc. 

 Del. Native of Europe. 

 Rare in our range as an escape. 



In waste ground: Conn, to 



2. Cannabis [Tourn.] L. 

 1. C. sativa L. In waste places: N. B. to Ont., Minn.. N. Car.. 

 Tenn. and Kan. 



Rare as an escape on waste ground. 



URTICACEAE 



Herbs with stinging hairs. 



Leaves opposite; both kinds of flowers 4-parted; achene straight. 

 Leaves alternate; staminate flowers 5 parted; achene oblique. 

 Herbs without stinging hairs. 



Flower clusters panicled or spiked, not involucrate; leaves 

 mostly opposite. 

 Pistillate calyx 3 parted or of 3 sepals. 

 Pistillate calyx 2-4 toothed or entire. 



Urtica. 

 Urticastrum. 



3. Pilea. 



4. boehmeria. 



Flowers clusters involucrate by leafy bracts, leaves alternate. 5. Parietaria. 



i. Urtica [Tourn.] L. 



Perennials, 0.6-2.2 m. tall; flower-clusters compound. 



Leaves ovate, cordate at base. I. U. dioica. 



Leaves lanceolate, rarely cordate. 2. U. gracilis. 



Annuals, 1.5-7 dm. tali; flower-clusters oblong, rather dense. 3- U. urens. 



