160 



CACTACEAE 



Stem with the ribs more or less divided into tubercles. 

 Tubercles terete. 



RacUal spines 8-9; central ones 1-3; tubercles 1 cm. liigh. 



Radial spines 10-14; central spines 4; tubercles low. 

 Tubercles rhombic in cross-section; radial spines 13-15. 



E. subglaucus. 

 E. Johnsoni. 

 E. Sileri. 



4. PEDIOCACTUS Britton & Rose. l. P. Simpsoni. 



5. CORYPHANTHA (Engelm.) Lem. 



Larger spines curved upwards; tubercles not grooved; flowers borne at the base of older 



tubercles, hence lateral on the stem. 1. C. Grahami. 



Spines all straight ; tubercles grooved ; flowers borne at the base of young tubercles, hence 

 nearly terminal. 

 Flowers yellowish or greenish, merely tinged with red; central spines 1; berry scarlet, 

 globose. 

 Stem usuaUy simple or nearly so; central spines stout, porrect; flowers about 2.5 

 cm. long. 2. C. niissouriensis. 



Stems tufted; central spine often wanting or small; flowers 3-4 cm. long. 



3. C. similis. 

 Flowers purple; central spines several; berry green, ellipsoid. 



Stems tufted, depressed-globose; central spines 3-4. 4. C. vivipara. 



Stems usually simple, ellipsoid or oblong; central spines 4-12, rarely 3. 



5. C. radiosa. 



Family SO. ELAEAGNACEAE. Ole.\ster Family. 



stamens 4; flowers perfect or polygamous; leaves alternate. 

 Stamens 8; flowers dioecious; leaves opposite. 



1. EL.\E.\GXTjS. 



2. Lep.\rgyre.\. 



1. ELAEAGNUS (Tourn.) L. Silver-berry, Silver-bush. i. E. commutata. 



2. LEPARGYREA Raf. Buffalo-berry, Bull-berry. 



Leaves green above; shrub not thorny. 



Leaves silvery white on both sides; plant usually thorny. 



Leaves oblong; fruit ellipsoid; tall sliriib or small tree. 



Leaves rounded-oval or ovate; fruit globular; low shrub. 



1. L. canadensis. 



2. L. argentea. 



3. L. roiundifolia. 



Family 90. LYTHRACEAE. Loosestrife Family. 



Hypanthium campanulate or tiu-binate, in fruit becomhig globose or hemispheric. 



Capsule bursting irregiilarly. 1. A]vaL\NL\. 



Capsule septicidal. 2. Rot.a.l.\. 



Hj-panthium cyhndric. 3. Lythrum. 



1. AMMANIA (Houston) L. 



2. ROTALA L. 



3. LYTHRUM L. Loosestrife. 



1. A. coccinea. 

 1. R. ramosior. 

 1. L. alatum. 



Family 9L ONAGRACEAE. Evening-Primrose Family. 



Flowers 4-merous. 



Frmt a many-seeded capsule, opening by valves. 

 Seeds with a tuft of silky hairs. 



Hypanthium not prolonged beyond the ovary ; flowers large. 



1. Cn.\iL\EXERION. 



Hj-panthium somewhat prolonged beyond the ovary. 



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

 witliin; flowers neither showy nor scarlet. 

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



or white, in ours yellow only in one species. 2. EPiLoniu.M. 

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



ish. 3. CORDYLOPiJOKUM. 



Hypanthiiun-tube inflated above the ovary, bearing 8 scal&s witliin; flow- 

 ers irregular, showy scarlet. 4. ZaU8chxeri.\. 

 Seeds without a tuft of silky hairs, naked or tuberciflate. 



Hypantliium not produced beyond tlie ovary; flowers minute. 



Stamens S; sepals deciduous; capsule linear. 5. Gayopiiytltm. 



Stamens 4; sepals persistent; capsule obovoid or turbmate. 



6. Isx.\rdi.\. 

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



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



Calyx-lobes erect; petals minute, clawless; capsule membranous. 



7. BOISUUV.\LU.\. 



