URTICACEAE. 99 



1. URTICA L. Nettle. 



Annual or perennial, simple or branching herbs, with 

 stinging hairs, and opposite 3-7-nerved petioled vSerrate 

 or dentate stipulate leaves. Flowers clustered in axillary 

 geminate racemes or heads. Staminate flowers 4-merous. 

 Pistillate calyx with unequal sepals, the inner larger and 

 at length enclosing the flattened achene. Stigma sessile, 

 tufted. 



1. U. urens L. Erect, branching from the base or sometimes 

 simple, 25-50 cm. high; leaves ovate or oblong-ovate, deeply and 

 sometimes doubly serrate, 1-4 cm. long, on slender petioles of about 

 the same length; stipules 4 mm. long; flower clusters rather dense, 

 mostly shorter than the petioles; flowers androgynous, mainly 

 pistillate. 



Common in gardens and waste places. Native of Europe. 



2. U. holosericea Nutt. Stems simple, stout, 1-3 m. high or 

 more, more or less bristly and finely pubescent; leaves finely and 

 densely pubescent beneath, less so above or with only a few scatter- 

 ing bristles, ovate to lanceolate, 5-10 cm. long, the upper much 

 shorter, on petioles I as long, coarsely serrate; stipules narrowly 

 oblong, acute or obtuse, 6-10 mm. long; staminate flower clusters 

 rather loose, nearly equaling the leaves; pistillate denser and shorter; 

 inner sepals ovate, densely hispid, 1 mm. long, about equaling the 

 broadly ovate achene. 



Very common along streams and in low ground in the valleys 

 and the lower altitudes of the mountains. May-September. 



2. HESPEROCNIDE Torn Western Nettle. 



Annual herbs distinguished from Urtica by the pistil- 

 late perianth, which is a membranous flattened oblong- 

 ovate sac, w^ith a minutely 2-4-toothed orifice. 



1. H. tenella Torr. Slender and weak, 25-50 cm. high, simple 

 or branched, somewhat hispid with branching hairs and bristly; 

 leaves 1-3 cm. long, thin, ovate, obtusely serrate; petioles slender, 

 \ as long; flower clusters rather dense, nearly glomerate, shorter 

 than the petioles; calyx thin, hispid, with hooked hairs, in fruit 

 1-1.5 mm. long; achene membranous, striately tuberculate with 

 minutely rough points. 



Sepulveda Canyon, Santa Monica Mountains; San Pedo Hills; 

 also near San Diego and on Catalina Island. 



3. PARIETARIA L. 



Ours slender annuals without stinging hairs. Leaves 

 alternate, entire, 3-nerved, petioled, without stipules. 

 Flowers in axillary glomerate clusters, polygamous, sub- 

 tended by leafy bracts. Calyx of the perfect flowers 



