222 ONAGBACE^E. (Enothera. 



7. CENOTHERA, Linn. 



Calyx-tube more or less prolonged above the ovary (obconic to linear), deciduous 

 (except in § 2) ; segments reflexed. Petals 4, obcordate to obovate, sessile, yellow 

 to white, often tinged with red or turning red in fading. Stamens 8, equal or those 

 opposite to the petals shorter; anthers perfect, versatile. Ovary 4-eelled, niany- 

 ovuled : style filiform : stigma 4dobed or capitate. Capsule coriaceous or somewhat 

 woody to membranaceous, dehiscing loeulicidally and more or less perfectly 4-valved ; 

 the partitions more or less coherent to the valves. Seeds in 1 or 2 rows in each cell, 

 horizontal or ascending, often somewhat margined. — Herbs, or sometimes woody at . 

 base; leaves alternate; flowers axillary, spicate, or racemose. — Watson, Proc. Am. 

 Acad. viii. 573. 



A genus of perhaps 100 species, almost exclusively American, there being over 50 in the United 

 States and most of the remainder Mexican or South American. Many of them are ornamental 

 and several have long heen in cultivation. Our species are usually found frequenting dry valleys 

 and hillsides. 



* Calyx-tube linear above the ovary : anthers and stigma-lobes linear : capsule rigid-coriaceous. 



Tall : flowers yellow, erect in the bud ; calyx-tips free : seeds in two 



rows in each cell. 1. (E. biennis. 



Low : flowers large, whitish, nodding in the bud : capsule narrow : 

 seeds in 1 row. 

 Perennial : calyx-tips free : capsule linear : seeds not compressed. 

 Smooth or puberulent : calyx not villous : seed terete, narrowly 



oblong. 2. CE. albicatjlis. 



Villous and pubescent : seeds oblong, turgid, somewhat angled. 3. CE. Californica. 

 Annual, villous and pubescent : calyx-tips not free : capsule thicker 



toward the base : seeds ovate-oblong, compressed. 4. CE. tkichocalyx. 



Aeaulescent or nearly so : flowers large, erect in bud : capsule ovate- 

 oblong, winged or crested : seeds in 2 rows. 

 Capsule strongly ribbed or tuberculately crested : more or less 



pubescent. 5. CE. cjespitosa. 



Capsule winged at the angles : nearly glabrous. 6. CE. triloba. 



* * Calyx-tube filiform : anthers oblong : stigma capitate : capsule ovoid-oblong, membranaceous, 



sessile : seeds in 2 rows. Aeaulescent, mostly perennial : flowers yellow, erect in bud, tips 

 of calyx not free. 



Densely pubescent : leaves deeply pinnatifid. 7. CE. Nuttallii. 



Glabrous : leaves oblanceolate, nearly entire. 8. CE. HETBEANTHA. 



Somewhat pubescent : leaves ovate- to oblong-lanceolate, entire, cili- 



ate : seeds punctate. 9. CE. ovata. 



Annual, dwarf, hirsute : leaves linear : capsules winged above. 10. CE. graciliflora. 



* * * Calyx-tube obconic : anthers oblong : stigma capitate : capsule narrow, membranaceous, 



sessile : seeds in 1 row : caulescent, mostly annual. 



Flowers axillary, yellow, mostly showy, often turning green : capsule 

 usually contorted, sharply 4-angled. 

 Canescently pubescent : leaves thick, mostly entire : maritime, 



often woody at base. 11. CE. cheiranthifolia. 



More or less hirsute : leaves thinner, denticulate. 



Petals 4 to 7 lines long, usually with a brown spot at base. 12. CE. ristorta. 



Petals a line or two long, not spotted. 13. CE. micramtha. 



Flowers axillary, yellow, mostly very small and usually turning red. 

 Capsule elongated, very narrowly linear, obtusely angled : slender, 

 with narrow leaves. 

 More or less hirsute : petals rarely reddening : capsules shortly 



beaked. 14. CE. DENTATA. 



Somewhat appressed-puberulent or hirsute : petals usually red- 

 dening : capsules obtuse, often pedicellate. 15. CE. strigtjlosA. 

 Capsule short, attenuated upward from the base : dwarf. 16. CE. andina. 

 Flowers in a nodding spike, white or rose-colored : capsule narrowly 

 linear, terete, much contorted. 



