LOOSESTRIFE FAMILY 583 



than half as long as the capsule. A. lalifolia T. & G., not L. (?) A. alcaliria 

 Blankinship. Swamps and wet places: Ind. — Fla. — Tex. — -Wyo. — Mont.; Mex.; 

 Brazil. Plain. Jl-S. 



2. ROTALA L. 



Annual or biennial swamp herbs, with 4-angled stems. Leaves opposite, 

 narrow, entire. Flowers perfect, usually sohtary in the axils. Hypanthium 

 campanulate, becoming subglobose in fruit. Sepals 4, very small. Petals 

 usually 4. Stamens 4; filaments short. Ovary subglobose, 4-celled; styles very 

 short; stigma entire or nearly so. Capsule 4-celled, subglobose, septicidally 

 4-valved. 



1. R. ramosior (L.) Koehne. A glabrous annual, 5-25 cm. high; leaves 

 oblong or linear-oblong, 1-3 cm. long, obtuse, acute at the base; flowers usually 

 solitary in the axils; cal^'x 3-4 mm. long; lobes acuminate; petals minute; cap- 

 sule ellipsoid. Wet places: Mass. — Fla. — Tex. — Neb. — Calif. — Ida. — Wash.; W. 

 Ind. and Mex. Jl-S. 



3. LYTHRUM L. Loosestrife. 



Herbs or shrubs, with angled stem; ours perennial herbs. Flowers solitary 

 in the axils, or in spikes or racemes. Hypanthium cylindric, ribbed or grooved. 

 Sepals 4-6, accompanied with as many accessory teeth. Petals 4-6, obovate or 

 oblanceolate. Stamens S-12, in one series; filament filiform. Ovary 2-celled; 

 stigma capitate. Capsule membranous, 2-celled, or becoming 1-celled, septicidally 

 2-valved or bursting irregularly. 



1. L. alatum Pursh. Perennial; stem glabrous, 3-12 dm. high, 4-angled or 

 -winged; leaves sessile, alternate or the lowest opposite, lanceolate or oblong, 

 rounded at the base, acute at the apex, 2-3 cm. long; flowers solitary in the upper 

 axils; petals deep purple, ascending; disk fleshy; calyx 5-6 mm. long in fruit, 

 ribbed. Low ground: Ont. — Mass. — D.C.— Tex. — Wyo. — B.C. Plain. Je-Au. 



Family 91. ONAGRACEAE. Evening-Primrose Family. 



Herbs, or rarely shrubs, with simple alternate or opposite leaves. Flow- 

 ers perfect, axillary or in terminal racemes. Hypanthium often elongate, 

 enclosing and adnate to the ovary. Sepals 2-6, usually 4. Petals 2-9, 

 usually 4, convolute in the bud, rarely wanting. Stamens as many or twice 

 as many as the sepals. Gynoecium of 1-6, usually 4, united carpels. Ovary 

 1-6-celled, inferior; styles united. Fruit capsular or nut-like. 



Flowers 4-nierous. 



Fruit a many-seeded cap.sulo, opening by valves. 

 Seeds with a tuft of silky hairs. 



Hypanthium not prolonged beyond the ovary; flowers large. 



1. Chamaenerion. 

 Hypantliium somewhat prolonged beyond the ovary. 



Hypanthium-tube cjlindric, not inflated above the ovary, without scales 

 within; flowers neither showy nor scarlet. 

 Flowers regular; stamens and style not declined; petals purpUsh, pink 



or white, in ours yellow only in one species. 2. Epilobium. 

 Flowers irregular; stamens and style somewhat declined; petals yellow- 

 ish. 3. COKDYLOPHOUUM. 



Hypantliium-tube inflated above the ovary, bearing 8 scales witliin; flow- 

 ers irregular, showy scarlet. 4. Z.\USCHNERIA. 

 Seeds without a tuft of silky liairs, naked or tuberculate. 



Hypanthium not produced beyond the ovary; flowers minute. 



Stamens 8 ; sepals deciduous ; capsule Unear. 5. Gayophyttjm. 



Stamens 4; sepals persistent; capsule obovoid or turbinate. 



6. Isnardia. 

 Hypantliium prolonged beyond the ovary into a cylindric or funnelform tube. 



Anthers attached near the bcise, erect; petals never yellow. 



Caly.x-lobes erect; petals minute, clawless; capsule membranous. 



7. BOISDUV.\LLL\. 



Calyx-lobes reflexed; petals showy, clawed; capsule coriaceous. 



Fertile stamens 4, the alternate ones rudimentary; petals 3-lobed. 



8. Clarkl\. 



