208 CAXNABINACEAE 



1. CANNABIS L. Hemp. 



Erect annual dioecious herbs. I.eaves alternate or opposite, digitately 5-11- 

 divided into serrate divisions. Staminate flowers in paniculate racemes; sepals 

 5, imbricate; stamens 5. Pistillate flowers in leafy-bracted spikes; perianth 

 undivided; pistil solitary. Fruit a slightly flattened achene. 



1. C. sativa L. Stem branched, 1-4 m. high, rough-pubescent; leaf- 

 blades divided into 5-11 hnear, serrate, acuminate divisions, 5-15 cm. long. 

 Waste places: N.B. — Ga. — Tenn. — Colo. — Minn.; escaped from cultivation; 

 native of Eurasia. 



2. HUMULUS L. Hops. 



Perennial, twining herbaceous vines. Leaves opposite, 3-7-lobed, serrate. 

 Stipule persistent, free. Staminate flowers in panicled racemes; sepals 5, imbri- 

 cate; stamens 5; filaments short, erect. Pistillate flowers in ament-like, droop- 

 ing spikes, 2 together, subtended by a bract; ovary 1-celled. Achenes a little 

 flattened. Embryo spirally coiled. 



Leaf-blades 3-7-lobed about half-way to the base, with ovate, acute or short-acuminate 

 lobes: those of the inflorescence 3-lobed or undi\'ided. 1. H. Lupuhis. 



Leaf-blades 5-7-divided to near the base, with lanceolate, long-acuminate di visions ; those 

 of the inflorescence .5-cleft. 2. H. neomexicanus. 



1. H. LupulU3 L. A vine 5-10 m. high; leaf-blades cordate in outline, 

 dark green, scabrous above, glabrous beneath except the pubescent veins; 

 lobes coarsely toothed, with ovate teeth; bracts of the pistillate flowers broadly 

 ovate, from obtuse to short acuminate. Common Hops. Rocky banks and 

 copses: N.S. — Ga. — Kans. — Wyo. — Mont.; Eurasia; extensively cultivated. 

 Plain — Submont. 



2. H. neomexicanus (A. Nels. & Cockerell) Rydb. A vine 5-10 m. high; 

 leaf -blades light green, minutely scabrous above, nearly glabrous beneath; bracts 

 of the pistillate flowers narrower, lanceolate or ovate, acute or acuminate. H. 

 Liipulus neomexicanus A. Nels. & Cockerell. Wild Hops. Among bushes: 

 Wyo. — Utah — Ariz. — -N.M. Plain — Submont. Jl-Au. 



Family 36. URTICACEAE. Nettle Family. 



^Monoecious, dioecious, or polygamous herbs (ours), often armed with 



stinging hairs. Leaves simple, alternate or opposite, with stipules. Flowers 



greenish, in axillary cjnnes. Calyx of 2-5 distinct or partly united sepals. 



Stamens 2-5, in the pistillary flowers reduced to staminodia or wanting. 



Pistil solitary; ovary 1-celled. Fruit an achene. Endosperm scant, oily, 



or wanting; emb yo straight. 



Herbs vnth stinging hairs; leaves opposite; flowers not involucrate. 1. Urtic.\. 



Plants without stinging hairs; leaves alternate; flowers involucrate by leafy bracts. 



2. P.^RIETARIA. 



1. URTICA (Tourn.) L. Nettle. 



Annual or perennial herbs, with stinging hairs. Leaves opposite, with 

 membranous, toothed, 5-7-veined blades and free stipules. Plants dioecious or 

 monoecious; flowers in axillary, paniculate cymes; sepals 4, nearly distinct, in 

 the pLstiUate flowers two of them larger. Staminate flowers with 4 stamens and 

 a rudimentary ovary, the pistillate ones with an equilateral ovary and tufted 

 stigmas. Achenes flattened. Seeds with membranous coats, often adherent 

 to the pericarp. All our species dioecious and perennial with a rootstock. 



Stipules membranous, oblong or broadly lanceolate, obtuse or acutish, often 1 cm. long. 

 Stem and leaves densely pubescent. , , , 



Stem and lower surface of the leaves coarsely velvety. 1. U. holoscncea. 



Stem flnelv strigose; lower surface of the leaves finely short-pubescent. 



2. U. Breweri. 

 Stem nearly glabrous; leaves puberulent, in age becoming glabrate. 



3. U. Lyalln. 



