342 FLORA. 



Herbs with stinging hairs. 



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



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

 Herbs without stinging hairs. 



Flower-clusters panicleci 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. Boehtneria. 



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



i. URTICA L. 



Herbs, with stinging hairs, 3-y-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 . chamaedryoides, 



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. [LAPORTEA Gaud.] 



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- 



