244 EPILOBIACEAE. 



3. Gayophytum Nuttallii T. & G. On hillsides from S. D. and Wash, to 

 Colo., Ariz, and Calif. — Alt. 6000-8000 ft. — Parlin, Gunnison Co. ; foot-hills, 

 Larimer Co. 



4. Gayophytum racemosum T. & G. In sandy soil from Wyo. and Wash, to 

 Colo, and Calif. — Alt. 5000-12,000 ft. — Headwaters of Clear Creek; Veta 

 Pass ; above Mancos ; along the Poudre. 



4. ONAGRA Adans. Evening Primrose. 



Hypanthium slender, 2.5-5 cm. long. 



Petals 1-2 cm. long, yellow ; pubescence rarely hirsute. 



Plant green ; capsule 3-4 cm. long. 1 . O. Oakesiana. 



Plant grayish strigose ; capsule 2-3 cm. long. 2. O. strigosa. 



Petals 2-3.5 cm. long, often pinkish; plant more or less hirsute. 



3. O. Hookeri. 

 Hypanthium stout, 6-13 cm. long. 4. O. Jamesii. 



1. Onagra Oakesiana (A. Gray) Britten. {Oenothera Oakesiana A. Gray) 

 In rich valleys from Que. and S. D. to N. Y. and Colo. — Alt. up to 10,000 ft. — 

 Salida; North Cheyenne Canon; Valley Spur. 



2. Onagra strigosa Rydb. In valleys and on plains from Minn, and Wash, 

 to Kans., N. M. and Utah. — Alt. 4000-7000 ft. — Ft. Collins ; Colorado Springs ; 

 Gunnison ; Elk River, Routt Co. ; Engelmann Caiion ; Poudre Canon ; Gyp- 

 sum; soldier Canon. 



3. Onagra Hookeri (T. & G.) Small. (Oenothera Hookeri T. & G. ; 0. 

 biennis hirsutissima A. Gray) In valleys from Ida. to N. M. and Calif. ; 

 also Mex. — Alt. 6000-10,000 ft. — Black Caiion of Gunnison; Caiion City, 

 Fremont Co. ; Pagosa Springs ; Parrott Post Office ; west of Ouray ; Waha- 

 toya Creek; Pike's Peak; Durango; along Conejos River north of Antonito. 



4. Onagra Jamesii (T. & G.) Small. (Oenothera Jamesii T. & G.) In 

 dry soil from Okl. and Utah to Tex. and Ariz. — On Platte River (?). 



5. ANOGRA Spach. White Evening Primrose. 



Calyx in bud merely acutish ; tips not free. 



Capsule divergent or reflexed. 1. A. violacea. 



Capsule erect or ascending. 2. A. albicanlis. 



Calyx in bud acuminate or acute ; tips free. 



Capsule linear-cylindric ; throat of the calyx glabrous. 



Calyx sparingly long-hairy, glandular-puberulent or glabrous, not strigose. 

 Leaves deeply pinnatifid. 3. A. rhisomata. 



Leaves subentire, dentate or short-lobed. 



Capsules strongly ascending, straight ; leaves linear, entire or nearly so, 



strigose beneath. 4. A. Nuttallii. 



Capsules divergent, usually curved upwards ; leaves usually denticulate 

 or sometimes lobed. 

 Leaves glabrous, except the margins. 5. A. Vreelandii. 



Leaves pubescent on both sides. 6. A. cinerea. 



Calyx and hypanthium densely grayish strigose ; leaves cinerous. 



7. A. latifolia. 

 Capsules oblong ; throat of the calyx hairy ; leaves deeply pinnatifid. 



8. A. coronopifolia. 



I. Anogra violacea A. Nels. In sandy soil of Wyo. and Colo. — Alt. 4000- 

 5500 ft. — Deer River ; Palisades ; Hotchkiss. 



