160 CACTACEAE 



Stem with the ribs more op less divided into tubercles. 

 Tubercles terete. 



Radial spines 8-9; central ones 1-3; tubercles 1 cm. high. 7. E. subglaucus. 



Radial spines 10-14; central spines 4; tubercles low. 8. E. Johnsoni. 



Tubercles rhombic in cross-section; radial spines 13-15. 9. 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 usually simple or nearly so; central spines stout, porrect; flowers about 2.5 

 cm. long. 2. C. missouriensis. 



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, eUipsoid or oblong; central spines 4-12, rarely 3. 



5. C. radiosa. 



Family 89. ELAEAGNACEAE. Oleaster Family. 



stamens 4; flowers perfect or polygamous; leaves alternate. 1. Elaeagnus. 



Stamens 8; flowers dioecious; leaves opposite. 2. Lepabgyrea.' 



1. ELAEAGNUS (Tourn.) L. Silver-bekey, Silver-bush. i. E. commutaia. 



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



Leaves green above; shrub not thorny. 1. L,. canadensis. 

 Leaves silvery white on both sides ; plant usually thorny. 



Leaves oblong; fruit ellipsoid; tall shrub or small tree. 2. I,, argentea. 



Leaves rounded-oval or ovate; fruit globular; low shrub. 3. L. rotundifolia. 



Family 90. LYTHRACEAE. Loosestrife Family. 



Hypanthium campanulate or turbinate, in fniit becoming globose or hemispheric. 



Capsule bursting irregularly. 1. AmmJlnia.. 



Capsule septicidal. 2. Rotala. 



Hypanthium cylindric. 3. Lytheum. 



1. AMMANIA (Houston) L. l. A. coccinea. 



2. ROTALA L. 1. B. ramosior. 



3. LYTHRUM L. Loosestrife. l. l. alatum. 



Family 91. ONAGRACEAE. Evening-Primrose Family. 



Flowers 4-merous. 



Fruit a many-seeded capsule, opening by valves. 

 Seeds with a tuft of silky hairs. 



Hypanthium not prolonged beyond the ovary ; flowers large. 



1. Chamaenerion. 

 Hypanthium somewhat prolonged beyond the ovary, 



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

 within; flowers neither showy nor scarlet. 

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



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

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

 ish. 3. Cobdylophorum. 

 Hypanthium-tube inflated above the ovary, bearing 8 scales within; flow- 

 ers irregular, showy scarlet. • 4. ZAUSCH>fERiA. 

 Seeds without a tuft of sUky hairs, naked or tuberculate. 



Hypanthium not produced beyond the ovary ; flowers minute. 



Stamens 8; sepals deciduous; capsule linear. 5. Gayophytum. 



Stamens 4; sepals persistent; capsule obovoid or turbinate. 



6. ISNARDtA. 



Hypanthium prolonged beyond the ovary into a cylindric or funneiform tube. 

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



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



7. BOISDUVALLL\. 



