URTICACEAE. 341 



often deeply 3-lobed, sometimes with a lobe on one side only, as in Sassafras, 

 rarely 5-lobed, rough above, tomentose beneath, 1-2 dm. long; spikes of staminate 

 flowers peduncled; heads of pistillate flowers 1-2.5 c . m - lli diameter. Escaped 

 from cultivation, N. Y. to Ga. and Mo. May-June. 



4. HUMULUS L. 



Herbaceous perennial rough vines, with broad opposite thin petioled palmately 

 veined leaves, lanceolate membranous stipules, and dioecious axillary flowers, the 

 staminate panicled, the pistillate in ament-like drooping clustered spikes. Stam- 

 inate flowers with a 5 -parted calyx, the segments distinct and imbricated, and 5 

 short erect stamens. Pistillate flowers in 2's in the axil of each bract of the ament. 

 consisting of a membranous entire perianth, clasping the ovary, and 2 filiform 

 caducous stigmas. Fruiting aments cone-like, the persistent bracts subtending the 

 compressed ovate achenes. Endosperm fleshy. Embryo spirally coiled. [Name 

 said to be the diminutive of the Latin humus, earth.] Two species, the following 

 widely distributed through the north temperate zone, the other native of north- 

 eastern Asia. 



I. Humulus Lupulus L. HOP. (I. F. f. 1261.) A vine, often 8 m. long, 

 very rough with stiff reflexed hairs. Leaves orbicular or ovate in outline, slender- 

 petioled, deeply 3-7 -cleft or some of the upper ones ovate, acute and merely ser- 

 rate; stipules refiexed, acuminate, 8-25 mm. long; ripe pistillate clusters (hops) 

 2.5-6 cm. long; fruiting bracts broadly ovate, concave, thin, glabrous or nearly 

 so, obtuse, much longer than the achenes; fruiting calyx and achene strongly 

 resinous-aromatic. In thickets and on river- banks, N. S. to Manitoba. N. Y., 

 Penn., in the Alleghanies to Ga., to Kans., and in the Rocky Mts. to Ariz, and 

 N. Mex. Extensively escaped from cultivation. Native also of Europe and Asia. 

 July-Aug. Fruit ripe Sept.-Oct. 



5. CANNABIS L. 



A stout, rough and puberulent herb, with petioled digitately 5-ii-divided thin 

 leaves, subulate stipules, and greenish dioecious axillary flowers, the staminate 

 panicled, the pistillate spicate. Staminate flowers with a 5 -parted calyx, the 

 sepals distinct and imbricated, and 5 short stamens. Pistillate flowers solitary in 

 the axils of foliaceous bracts, consisting of a thin entire calyx clasping the sessile 

 ovary, and 2 filiform caducous stigmas. Fruit a compressed achene. Endosperm 

 fleshy; embryo curved. [The classic name of hemp.] A monotypic genus of 

 central Asia. 



i. Cannabis sativa L. HEMP. (I. F. f. 1262.) Annual, branching, 1-3 m. 

 tall, the inner fibrous bark very tough. Leaves divided to the base, the segments 

 lanceolate or linear-lanceolate, acuminate at both ends, sharply and coarsely ser- 

 rate, 0.7-1.5 dm. long; staminate panicles narrow, loose, peduncled; pedicels 

 filiform, bracteolate, 2-6 mm. long; pistillate spikes erect, leafy -bracted; achene 

 crustaceous. ovoid-oblong, about 4 mm. high. In waste places, N. B. to Ont., 

 Minn., N. Car., Tenn. and Kans. July-Sept. 



Family 3. URTICACEAE Reichenb. 

 Nettle Family. 



Herbs (some tropical species shrubs or trees), with watery sap, 

 mostly stipulate simple leaves, and small greenish dioecious, monoe- 

 cious or polygamous flowers, variously clustered. Calyx 2-5-cleft, 

 or of distinct "sepals. Petals none. Stamens in the staminate flowers 

 as many as the lobes or segments of the calyx (sepals) and opposite 

 them, the filaments inflexed and anthers reversed in the bud, straighten- 

 ing at anthesis. Ovary superior, i -eel led ; style simple; ovule solitary, 

 erect or ascending, orthotropous, or in some genera partly amphitro- 

 pous. Fruit an achene. Endosperm oily, usually not copious ; embryo 

 straight. About 40 genera and 475 species of wide geographic dis- 

 tribution. 



