524 



URTICACEAE 



1. URTICA [Tourn.] L. Sp. PI. 983. 1753. 



Annual or perennial, simple or branching herbs, with stinging hairs, and opposite 2)-7- 

 nerved petioled serrate or dentate stipulate leaves. Flowers clustered in axillary geminate 

 racemes or heads. Staminate flowers with a deeply parted calyx and 4 stamens. Pistillate 

 calyx with unequal sepals, the inner larger and at length enclosing the flattened achene. 

 Stigma sessile, tufted. [The ancient Latin name.] 



About 30 species of wide geographic distribution. Type species, Urtica dioica L. 

 Perennials; pistillate and staminate flowers in separate clusters. 

 Stem and leaves densely pubescent. 



Stem and leaves coarsely velvety pubescent; seeds tan-colored, smooth. 1. U. holosericea. 



Stem finely strigose; lower surface of leaves short pubescent; seed olive-brown, finely tuberculate. 



2. U. breweri. 

 Stem nearly glabrous; leaves dark green above and glabrate in age; seeds tan-colored, smooth. 

 Leaves grayish pubescent below, deeply cordate, not with a prolonged entire apex. 



Leaves green on both surfaces, with an entire caudate apex. 

 Annual; pistillate and staminate flowers mixed in same cluster. 



3. U. californica. 



4. U. lyallii. 



5. U. urens. 



■HH-st 





1. Urtica holosericea Nutt. Hoary 

 Nettle. Fig. 1270. 



Urtica holosericea Nutt. Journ. Acad. Phila. II. 1 : 



183. 1847. 

 Urtica gracilis holosericea Tepson, Fl. Calif. 1 : 367. 



1909. 



Stems simple, stout, 1-3 m. high or more, 

 more or less bristly and finely pubescent. 

 Leaves cinereous densely pubescent beneath and 

 soft velvety, less so above or with only a few 

 scattering bristles, ovate to lanceolate, 5-10 cm. 

 long, the upper much shorter, on petioles one- 

 fourth as long, coarsely serrate ; stipules nar- 

 rowly oblong, acute or obtuse, 6-10 mm. long ; 

 staminate flower clusters rathtr loose, nearly 

 equalling the leaves; pistillate denser and 

 shorter ; inner sepals ovate, densely hispid, 1 

 mm. long, about equalling the broadly ovate 

 achene. 



Low ground and stream banks. Transition and 

 Upper Sonoran Zones; Washington and Idaho, south 

 to northern Lower California. The plants of the 

 Sierra Nevada and southern California mountains are 

 greener, with the stems sometimes nearly glabrous. 

 July-Sept. Type locality: Monterey, California. 



2. Urtica breweri S. Wats. Brewer's Nettle. Fig. 1271. 



Urtica breiceri S. Wats. Proc. Am. Acad. 10: 348. 

 1875. 



Stem 1-2 m. high, stout, nearly glabrous or 

 grayish with a short strigose pubescence and 

 scattered bristles. Leaves 4—10 cm. long, ovate 

 to ovate-lanceolate, rounded or subcordate at 

 base, coarsely toothed, sparsely strigose above, 

 becoming glabrate, velvety pubescent beneath, 

 with a short fine grayish pubescence ; petioles 

 usually strongly bristly, about one-third the 

 length of the blades ; flower clusters dense, 

 tnuch shorter than the leaves ; achencs usually 

 much shorter than the inner sepals, dull olive 

 brown, sparsely papillate-roughened. 



Low ground and stream banks. Upper Sonoran 

 Zone; southern California and L'tah to western Texas 

 and adjacent Mexico. June-Get. Type locality: near 

 Los Angeles. 



