102 • CANNABINACEAE. 



late: achenes ovoid, about 2 mm. long. — Common, in moist shaded places. — 

 Sum. — Clearweed. Eichweed. 



i. PARIETAEIA [Tourn.] L. Annual or perennial flimsy succulent herbs. 

 Leaves alternate : blades entire. Flowers polygamous, in clustered involucrate 

 axillary cymes, the involucres of 2-6 more or less united bracts. Stigma 

 tufted. 



1. P. pennsylvanica Muhl. Stems 1-4 dm. long, finely pubescent, simple or 

 branched: leaf -blades lanceolate to elliptic or sometimes broader, 1-6 cm. 

 long, acute or acuminate at the base : sepals acute : achenes oval, fully 1 mm. 

 long. — S. Bather common, on dry banks. — Schists. — Sum. — Pellitory. 



5. BOEHMERIA Jacq. Perennial herbs. Leaves opposite: blades 

 toothed, often 3-ribbed. Flowers monoecious, in clusters on branches, the 

 pistillate with 4 united sepals surrounding the ovary. Stigma elongate. 

 Achene included in the horseshoe-like accrescent calyx. — Sum. and fall. — 

 False-nettle. 



Staminate calyx about 3 mm. wide ; sepals acute': leaf-blades leathery, finely ser- 

 rate : petioles much shorter than the blades. 1. B. scabra. 



Staminate calyx about 2 mm. wide : sepals obtuse : leaf-blades 

 relatively thin, coarsely serrate : petioles as long as the blades 

 or little shorter. 2. B. cylindrica. 



1. B. scabra (Porter) Small. Stems 2-12 dm. tall, typically rough-pubescent: 

 leaf-blades firm, ovate to elliptic-ovate, or the lower ones orbicular to reni- 

 form, 2-5 cm. long, or rarely larger, short-petioled: flower-clusters mostly 

 contiguous: inflorescence-branches short: achenes mostly about 1.5 mm. wide. 

 — S. Eather common, in moist grounds and swamps. — Schists. 



2. B. cylindrica (L.) Willd. Stems 2-13 dm. tall, typically smooth and gla- 

 brous: leaf -blades pliable, ovate to lanceolate, 3-12 cm. long, long-petioled : 

 flower-clusters mostly separate: inflorescence-branches elongate: achenes mostly 

 about 1 mm. wide. — N. M. Eather common, in moist soil. — Sandstones and 

 shales, limestones. 



Family 2. CANNABINACEAE. Hemp Family. 



Annual or perennial, often coarsely pubescent herbs. Leaves oppo- 

 site or sometimes alternate: blades toothed, lobed, or divided. Flowers 

 dioecious, the pistillate in braeted spikes, with an entire perianth, and a 

 gynoecium of 2 united carpels, the ovary 1-eelled. Fruit an achene. 



Stem twining : leaf-blades usually 3-lobed : fruit a drooping cone with thin imbricate 



bracts. 1. Humclus. 



Stems erect : leaf-blades 3-7-parted : fruit spicate on stiff branches. 2. Cannabis. 



1. HUMTJLUS L. Perennial vines. Leaves opposite: blades serrate or 

 lobed. Pistillate flowers 2 together in ament-like drooping spikes which 

 become cone-like at maturity. 



1. H. Lupulus L. Stem and branches pubescent with recurved hairs: leaf- 

 blades orbicular or ovate in outline, 3-15 cm. in diameter, 3-6-lobed and 

 serrate, or merely serrate: mature pistillate spikes 3-8 cm. long, ovoid to 

 cylindric : achenes subglobose, 2-3 mm. in diameter. — Eather common, in 

 thickets and fence-rows. Nat. of Eurasia. — Sum. — Hop. 



2. CANNABIS [Tourn.] L. Annual coarse herbs. Leaves opposite or 

 alternate: blades digitately divided. Pistillate flowers solitary, in the axils 

 of leaf -like bracts, disposed in elongate spikes at maturity. 



