NETTLE FAMILY 209 



Stipules narrowly lanceolate or linear, attenuate. 



Teeth of the leaves ovate, strongly directed forward. 



Stem glabrous except the presence of a few bristles; leaves thin, almost glabrous, 



not strongly veined. 



Petioles one-third to one-half as long as the cordate or broadly ovate leaf- 

 blades. 4. U. cardiophylla. 

 Petioles one-fifth to one-third as long as the lanceolate or ovate-lanceolate 



leaf-blades. 5. U. viridis. 



Stem more or less strigose or hirsute ; leaves decidedly hairy, especially on the very 



strong veins. 

 Leaf-blades lanceolate, scarcely cordate at the base. 



Stem sparingly strigose and bristly. 6. U. gracilis. 



Stem densely strigose, scarcely at all bristly. 7. U. strigosissima. 



Leaf-blades broad, deeply cordate at base. 8. U. dioica. 



Teeth of the leaves broadly triangular, not strongly directed forward ; stem and leaves 

 glabrous or nearly so. 9. U. gracilenta. 



1. U. holosericea Nutt. Plant densely velvety; stem 1-3 m. high; leaf- 

 blades thick, ovate or the lower cordate, coarsely toothed, 5-10 cm. long, pale 

 beneath; staminate flowers in loose panicles, nearly equalling the upper leaves, 

 the pistillate ones in shorter and denser clusters; inner sepals ovate, about equal- 

 ling the achenes. Alluvial soil: Wash. Ida. -Calif. Son. -Submont. Jl-Au. 



2. U. Breweri S. Wats. Stem 1-2 m. high; leaf-blades lanceolate to cordate, 

 coarsely toothed, rather thin, somewhat paler beneath; panicles shorter than in 

 the preceding, the staminate ones shorter than the leaves, the pistillate slightly 

 exceeding the petioles; sepals obovate, about twice as long as the achenes. River 

 valleys: Wash. Utah Calif. Submont. Je-Au. 



3. U. Lyallii S. Wats. Perennial, dioecious; stem 1-2 m. high; leaf-blades 

 thin, coarsely toothed, 3-15 cm. long, ovate or cordate; panicles shorter than the 

 leaves, the pistillate ones scarcely exceeding the petioles; sepals ovate, usually 

 shorter than the achenes. Along streams: Alaska 'Wash.; Newf. -Conn. 

 Submont. My-S. 



4. U. cardiophylla Rydb. Stem about 1 m. high; lower leaf-blades cordate, 

 the upper lance-ovate, 6-10 cm. long, coarsely toothed, very thin, shining, dark 

 green, glabrous; panicles small, few-flowered, much shorter than the leaves; 

 sepals ovate, about equalling the achenes. Wooded creek banks: Mont. Alta. 



-B.C. Ida. Submont. Je-Au. 



5. U. viridis Rydb. Stem 1-1.5 m. high, slender; blades coarsely toothed, 

 4-10 cm. long, thin, light green; panicles many-flowered, often equalling the 

 upper leaves; sepals oval or ovate, usually half longer than the achene. River 

 bottoms: Ida. Wyo. Alta. Submont. Je-Au. 



6. U. gracilis Ait. Stem slender, 0.5-3 m. high, sharp-angled; leaf-blades 

 finely serrate, acuminate, 7-15 cm. long, about as wide as the length of the 

 petioles; flower-clusters slender, but shorter than the leaves; sepals ovate^about 

 equalling the achenes. Alluvial soil and waste places: N.S. N.C. N.M.- 

 Alaska. Plain Mont. Ap-S. 



7. U. strigosissima Rydb. Stem 1 m. high or more; petioles 2-3 cm. long; 

 leaf-blades sharply serrate, long-acuminate, 5-10 cm. long, 1.5-5 cm. wide; 

 flower-clusters slender, the upper almost equalling the leaves; sepals ovate, 

 about equalling the achenes. River banks: Ida. Utah. Submont. July. 



8. U. dioica L. Stem 0.5-1.5 m. high, strongly bristly and somewhat 

 hispidulous above, obtusely angled; leaf-blades thin, very bristly, coarsely 

 toothed, acute or short-acuminate, 3-10 cm. long, usually twice as broad as the 

 length of the petioles; flower-clusters about half as long as the leaves. Waste 

 places: N.S. S.C. Colo. Minn.; nat. from Eu. Plain Submont. Jl-S. 



9. U. gracilenta Greene. Stem slender, 1-2 m. high, strigose or hirsutulous, 

 as well as bristly; petioles slender, 2-8 cm. long; leaf -blades lanceolate, long- 

 acuminate, rounded at the base, 5-15 cm. long, more or less pubescent, with 

 salient teeth; flower-clusters slender, slightly exceeding the petioles. Along 

 streams and in canons: S.D. Wyo. Ariz. Tex.; Mex. Son. Submont. Au- 

 S. 



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