176 CONTEIBUTIONS FROM THE NATIONAL HEEBARIUM. 



36. URTICACEAE. Nettle Family. 



Usually coarse, moncecious, dioecious, or polygamous herbs, often armed with 

 stinging hairs; leaves simple, opposite or alternate; flowers inconspicuous, greenish, 

 in axillary simple or compound cymes. 



KEY TO THE GENERA. 



Plants armed with stinging hairs; leaves opposite; inflores- 

 cence not involucrate 1. Urtica (p. 176). 



Plants without stinging hairs; leaves opposite or alternate; 

 inflorescence various. 



Flower clusters not involucrate; leaves opposite 2. Boehmeria (p. 176). 



Flower clusters surrounded by an involucre; leaves 



alternate 3. Parietaria (p. 177). 



1. TJIITICA L. Nettle. 



Coarse annual or perennial herbs armed with stinging hairs; leaves opposite, toothed; 

 flowers in axillary cymes, these often panicled; achenes flattened. 



Our species are inconspicuous plants found chiefly in moist, shaded places iu the 

 mountains. 



KEY TO the species. 



Teeth of the leaves ovate, strongly directed forward; stems armed 

 with rather few stinging hairs, otherwise glabrous; leaves 

 lanceolate 1. U. gracilis. 



Teeth of the leaves broadly triangular, salient, not strongly directed 

 forward; stems armed with numerous stinging hairs, strigose; 

 leaves commonly ovate 2. U. gracilenta. 



1. Urtica gracilis Ait. Hort. Kew. 3: 341. 1789. 

 Type locality: "Native of Hudson's Bay." 



Range: British America to Arizona, Texas, and Louisiana. 



New Mexico: Carrizo Mountains; Chama; Santa Fe and Las Vegas mountains; 

 Clayton; Sandia Mountains; Mogollon Mountains; White Mountains. Damp woods and 

 canyons, in the Transition Zone. 



2. Urtica gracilenta Greene, Bull. Torrey Club 8: 122. 1881. 



Type locality: Mimbres Mountains, New Mexico. Tjrpe collected by E. L. 

 Greene. 



Range: New Mexico and Arizona. 



New Mexico: Mogollon Mountains; Organ Mountains; White Mountains. Damp 

 thickets, in the Upper Sonoran and Transition zones. 



2. BOEHMERIA Jacq. False nettle. 



A coarse stout unarmed perennial herb, 30 to 80 cm. high, with opposite, petioled, 

 pubescent, coarsely serrate, lanceolate leaves; flowers in axillary spikes; stems finely 

 pubescent. 



1. Boehmeria scabra (Porter) Small, Fl. Southeast. U. S. 358. 1903. 

 Boehmeria ajlindrica scabra Porter, Bull. Torrey Club 16: 21. 1889. 

 Type locality: "Crawford and Lancaster counties," Pennsylvania. 

 Range: New York to Michigan, Florida, and New Mexico. 

 New Mexico: Roswell (^arZe 265). 



