34 2 FLORA. 



Herbs with stinging hairs. 



Leaves opposite ; both kinds of flowers 4-parted ; achene straight, i. Urtica. 



Leaves alternate; staminate flowers 5-parted ; achene oblique. 2. Urticastrunt. 

 Herbs without stinging hairs. 



Flower-clusters panicled or spiked, not involucrate ; leaves mostly opposite. 



Pistillate calyx 3-parted or of 3 sepals. 3. Adicea. 



Pistillate calyx 2-4-toothed or entire. 4. Boehmeria. 



Flower-clusters involucrate by leafy bracts; leaves alternate. 5. Parietaria. 



i. URTICA L. 



Herbs, with stinging hairs, 3-7 -nerved petioled dentate or incised leaves, and 

 distinct or connate stipules. Flowers small and numerous, axillary, cymose- 

 paniculate, or glomerate, dioecious, monoecious or androgynous. Staminate flowers 

 with a deeply 4-parted calyx and 4 stamens. Pistillate calyx 4-parted, the seg- 

 ments unequal; ovary straight; stigma sessile or nearly so; ovule erect, orthot- 

 ropous. Achene compressed, enclosed by the persistent calyx. Seed-coat thin; 

 endosperm little; cotyledons broad. [The ancient Latin name.] About 30 species 

 of wide distribution. 



Perennials, 0.6-2.2 m. tall ; flower-clusters large, compound. 



Leaves ovate, cordate at base. i. U. dioica. 



Leaves laciniate, rarely cordate. 2. U. gracilis. 

 Annuals, 1.5-7 dm. tall ; flower-clusters small, mostly glomerate. 



Leaves oval, laciniate-dentate; plant leafy at the top. 3. U. urens. 



Leaves ovate or lanceolate, crenate ; upper leaves very small. 



4. U . chamaedry aides. 



1. Urtica dioica L. STINGING OR GREAT NETTLE. (I. F. f. 1263.) Densely 

 beset with stinging hairs; stem 0.6-1.2 m. tall, puberulent above. Leaves thin, 

 ovate, long- petioled, acute or acuminate at the apex, cordate at the base, sharply 

 serrate with acute teeth, pubescent beneath, 3-5 -nerved, 7-13 cm. long; stipules 

 lanceolate; flower-clusters large, cymose -paniculate; flowers dioecious or andro- 

 gynous. In waste places, N. S. to Ont., Minn., S. Car. and Mo. Nat. from Europe. 

 Native also of Asia. July-Sept. 



2. Urtica gracilis Ait. SLENDER NETTLE. (I. F. f. 1264.) Sparingly 

 armed with stinging hairs; stem usually slender, 0.6-2.2 m. tall. Leaves lanceo- 

 late or ovate-lanceolate, slender-petioled, long-acuminate at the apex, narrowed or 

 sometimes rounded at the base (rarely subcordate), sharply serrate, 3-5-nerved, 

 sparingly pubescent, 7-15 cm. long; petioles usually bristly; stipules lanceolate; 

 flower- clusters compound, smaller than those of the preceding, but commonly 

 longer than the petioles; flowers dioecious or androgynous. In dry soil, N. S. to 

 Br. Col., N. Car., La. and Kans. June-Oct. 



3. Urtica urens L. SMALL NETTLE. (I. F. f. 1265.) Stem 1.5-4.5 dm. 

 high, stinging-bristly. Leaves thin, glabrous or very nearly so, elliptic, oval or 

 ovate, deeply incised or sometimes doubly serrate, 3-5 -nerved, 2-8 cm. long, 

 slender-petioled ; stipules short ; flower-clusters oblong, rather dense. In waste 

 places, Newf. to N. Y., N. J. and Fla. Also on the Pacific Coast. Nat. from 

 Europe. May-Sept. 



4. Urtica chamaedryoides Pursh. WEAK NETTLE. (I. F. f. 1266.) Sparingly 

 stinging-bristly; stem slender, weak, ascending, 1.5-10 dm. long. Leaves slender- 

 petioled, thin, crenate-dentate, the lower broadly ovate or orbicular, obtuse at the 

 apex and usually cordate at the base, 1-3 cm. wide, the upper ovate or lanceolate, 

 acute or acuminate at the apex, the uppermost very small ; stipules lanceolate- 

 subulate; flower-clusters small, glomerate. In thickets, Ky. to Ark., Ga. and Tex. 

 April-Aug. 



2. URTICASTRUM Fabr. 



Perennial herbs, armed with stinging hairs, the leaves broad, alternate, serrate, 

 petioled, the flowers monoecious or dioecious, sessile in loose axillary compound 

 cymes. Staminate flowers in our species with 5 imbricated sepals, 5 stamens and 

 a rudimentary ovary. Pistillate flowers with 4 unequal sepals, the outer i or 2 

 minute, an oblique or nearly straight compressed ovary and a subulate slender per- 

 sistent style ; ovule erect. Achene very oblique, flat, reflexed. Seed-coat mem- 



