URTICACE^E. 



147 



small, greenish, unisexual, arranged in amcnt-like inflorescences. 

 Petals none. Calyx in ours 2 to 4- toothed or -cleft, or of nearly 

 distinct segments with as many stamens opposite the lobes, the fila- 

 ments coiled or bent inward in the bud so that when released, they 

 fly upwards like a spring, scattering the pollen. Ovary superior, 

 1-celled, 1-ovuled; style and stigma 1. Fruit an achene. Embryo 

 straight. 



Calyx 4-parted, the segments almost distinct, the inner ones largest in the fertile 

 "flower and enclosing the achene 1. Urtica. 



Pistillate calyx sac-like, unequally 2 to 4-toothed, enclosing the achene; 

 staminutecalyx 4-parted 2. Hesperocnide. 



1. URTICA L. Nettle. 

 Annual or perennial herbs with stinging hairs, opposite petioled 

 3 to 7-nerved serrate leaves and distinct lateral stipules. Flowere 

 in ours monoecious, clustered in axillary geminate racemes or heads. 

 Staminate flowers of 4 sepals and 4 stamens. Pistillate calyx with 

 the sepals unequal, the exterior smaller than the inner and at length 

 enclosing the flattened achene; ovary with sessile tufted or almost 

 feathery stigma, and erect orthotropous ovule. Endosperm scanty. 

 (Ancient Latin name.) 



Annual; inflorescence androgynous; stipules very small . . . . 1. U. urens. 

 Perennial; inflorescence unisexual; stipules laige. 

 Herbage dark-green; upper leaves narrowly- to round-ovate, mostly cordate 

 at base; stipules broadly oblong to elliptical; near the coast, rare .... 



2. K Lyallii 

 var. Calif arnica. 



Herbage gray; upper leaves ovate-lanceolate, obtuse to truncate at ba-e; 

 stipules narrowly oblong: common everywhere 8. U. holoscricea. 



1. U. urens L. Small Nettle. Erect and simple or branching 

 from the base, 1 to 1£ ft. high, leafy to the top; leaves elliptic or 

 ovate, coarsely laciniate-serrate, 3 to 5-nerved, 1 to 2 in. long, slender 

 petioled; stipules short, about 1 line long; inflorescence oblong, rather 

 dense, mostly shorter than the petioles; flowers androgynous, that is, 

 staminate and pistillate mixed in the same cluster. 



Introduced weed. Berkeley. 



2. U. Lyallii Wats. var. Californica. Often branched from the 

 base, 2 to 3 ft. high; herbage dark green, the stems and foliage some- 

 what pubescent; leaves broadly ovate, cordate at base, coarsely serrate, 

 3 to 5 in. long, stipules broadly oblong to elliptical, obtuse, 3 to 6£ 

 lines long; flowers in spreading panicles; sepals broadly ovate or 

 rounded, obtuse, shorter than the broadly ovate achene, which is § 

 line long. — (U. Californica Greene.) 



Point Reyes Peninsula, Greene and Jepson; marshes near Tennessee 

 Bay, Marin Co., Eastwood; Pilarcitos, Davy. Mar. The species is 

 far northern. 



3 U. holosericea Nutt. Creek Nettle. Herbage gray; stems 

 strict, unbranched, 4 to 6 or even 10 ft. high; leaves ovate to lanceo- 

 late, 3 to in. long, on petioles J to 1 or 2 in. long, more or less 

 pubescent on both faces or the upper surface green and with scattered 

 bristles and the lower surface gray; stipules narrowly oblong, acute 



