168 KEY AXD FLORA 



71. ONAGRACE^. Evening Primrose Family 



Herbs, rarely shrubs or trees. Leaves opposite or alternate, 

 without stipules. Flowers actinomorphic. Limb of the calyx 

 epigynous, 2-4-lobed. Petals 2-4, rarely wanting, quickly fall- 

 ing off. Stamens 1-8. Ovary usually 4-celled ;■ style thread- 

 like ; stigma entire or 4-lobed ; ovules 1 or more in the inuer 

 angle of each cell. Fruit a capsule, berry, or drupe. Seeds 

 1 or more, smooth or hairy. 



I. CENOTHERA L. 



Herbs, rarely shrubby. Leaves alternate. Flowers large, yel- 

 low, red, or purple. Calyx tube 4-angled. Petals 4. Stamens 

 8. Capsule usually 4-celled, many-seeded. 



B. Fl. species 1 (Onagra); species 2, 3 (Kneiffid) ; species 4 

 (Hartmannid); species 5 (^ller/aptrrmiii^. 



1. CE. biennis L. Common Evening Primrosr. Annual or bien- 

 nial. Erect and usually stout, 1--5 ft. high, stem usually simple, 

 more or less downy and hairy. Leaves lanceolate, acute or taper- 

 pointed, sessile or the lower ones petioled. Flowers bright yellow, 

 1-2 in. in diameter, opening in the evening. Pod oblong, narrowed 

 above, erect, nearly cylindrical. In dry soil. 



2. (E. pumila L. Small Sdndrops. Perennial. Stem erect, finely 

 downy, 4-24 in. high. Leaves usually smooth, entire, obtuse or nearly 

 so, the basal ones spatulate, those of the stem varying from oblanceo- 

 late to lanceolate. Spikes loose, nodding when young. Flowers ^-1 

 in. in diameter. Pods slightly glandular-downy, club-shaped, {-^ in. 

 long. In dry soil. 



3. (E. fruticosa L. Sundrops. Biennial or perennial. Stem erect, 

 often rather stout, 1-3 ft. high, downy or sometimes smooth. Leaves 

 lance-oblong, or in one variety linear or nearly so, usually minutely 

 toothed. Racemes often corymbed. Flowers open in the daytime, 

 showy, yellow, 1-2 in. in diameter. Pod nearly sessile, ellipsoidal, 

 with prominent ribs and strong wings. Dry soil, common. 



4. CE. speciosa JSTutt. Showy Primrose. Perennial. Stem downy, 

 erect or somewhat decumbent, 6 in. -3 ft. high. Leaves broadly 

 lanceolate to lijiear, sinuate-denticulate or sinuate-pinnatifld, 2-3 in. 

 long. Flowers opening in the daytime, few, l^-SJ in. in diameter, 

 white to pale pink. Pod strongly 8-ribbed. Prairies S.W. 



