596 ONAGRACEAE 



cinereous; sepals 1.5 cm. long, cinereous and silky-villous; capsule erect, 2-3 cm. 

 long, 2 mm. thick, nearly straight. 0. trichocalyx Nutt. Dry places: Wyo. 

 Colo. Nev. Plain Submont. My-Jl. 



6. A. perplexa Rydb. Biennial; stem 1-2 dm. high, more or less cinereous 

 and with scattered hairs, branched at the base, with erect branches; leaves 2-6 

 dm. long, oblanceolate in outline, hirsute and somewhat canescent, the basal 

 ones dentate, the cauline ones strongly ascending, deeply pinnatifid, with nar- 

 rowly linear, more or less ascending lobes; tube of the hypanthium 1.5-2 cm. 

 long, hirsute; calyx-lobes 1.5-1.75 cm. long, hirsute; capsule about 3 cm. long, 

 and fully 3 mm. thick, erect. Plains: Neb. Kans. Colo. Wyo. Plain 

 Submont. Je-Jl. 



7. A. albicaulis (Pursh) Britton. Annual or biennial; stem 1-3 dm. long, 

 branched at the base; basal leaves spatulate, obtuse, merely toothed; stem-leaves 

 5-12 cm. long, deeply pinnatifid, with lanceolate or linear, rather divergent 

 divisions; tube of hypanthium about 3 cm. long, sparingly pubescent; calyx-lobes 

 about 3 cm. long, sparingly silky-hirsute or sometimes glabrous; pod 3.5-5 cm. 

 long, about 3 mm. thick. Oenothera pinnatifida Nutt. O. albicaulis Pursh. 

 Hillsides and in sandy soil: S.D. Tex. Ariz. Mont:; n Mex. Plain Sub- 

 mont. My-Jl. 



8. A. Bradburiana (Nutt.) Rydb. Annual or biennial; stem erect, 1-2 dm. 

 high, finely cinereous-strigose ; leaves 3-5 cm. long, oblanceolate in outline; the 

 basal ones subentire or dentate, the cauline ones deeply pinnatifid, cinereous- 

 strigose; tube of hypanthium and calyx-lobes cinereous, each nearly 2 cm. long; 

 petals fully 2 cm. long. 0. Bradburiana Nutt. Sandy places: Wyo. S.D. 



9. A. simplex Small. Annual; stem simple, 1-1.5 dm. high; leaves peti- 

 oled, oblanceolate, sinuately toothed or entire, 5-10 cm. long, grayish strigose; 

 tube of hypanthium 2-2.5 cm. long, canescent; calyx-lobes about 2 cm. long, 

 strigose, their free tips fully 1 mm. long; petals 2.5-3 cm. long, white, turning 

 rose, with yellow bases. Dry places: s Utah L. Calif. L. Son. 



10. A. rhizomata A. Nels. Perennial, with a rootstock; stems 1-2 dm. 

 long, often pinkish or violet, strigose and sparingly hirsute; leaves oblanceolate 

 in outline, 3-5 cm. long, strigose and hirsute, the lowermost entire or dentate; 

 tube of hypanthium 1.5-2 cm. long; calyx-lobes silky-hirsute, 1.5-2 cm. long; 

 free tips scarcely 1 mm. long; capsules spreading, about 3 cm. long. Dry 

 sandy places: Wyo. Colo. Plain Submont. My-Jl. 



11. A. Nuttallii (Sweet) A. Nels. Perennial; stem 3-10 dm. high; leaves 

 5-10 cm. long; tube of hypanthium glabrous or sparingly glandular-puberulent, 

 3-4 cm. long; calyx-lobes 1.5-2 cm. long, glabrous or sparingly hirsute; free tips 

 3 mm. long; capsule 3 cm. long; petals 2-2.5 cm. long. Oenothera albicaulis 

 Nutt. In sandy soil: Sask. Minn. Colo. Ida. B.C. Plain Mont. Je- 

 Au. 



12. A. pallida (Dougl.) Britton. Perennial, with a horizontal rootstock; 

 stem 3-5 dm. high, glabrous; leaves perfectly glabrous, entire, dentate, or the 

 upper somewhat sinuate-pinnatifid, 3-10 cm. long; tube of the hypanthium 2-3 

 cm. long; calyx-lobes 1.5-2 cm. long; free tips 1.5-2 mm. long; petals obcordate, 

 1.5-2 cm. long; pod 2.5-3 cm. long, 3 mm. thick. Sandy places: Mont. Utah 

 Calif. B.C. Plain Submont. Je-Jl. 



13. A. leptophylla (Nutt.) Rydb. Perennial; stem 2-4 dm. high, glabrous, 

 shining; leaves 2-5 cm. long, pubescent on the margins, otherwise glabrous; tube 

 of hypanthium 1.5-2 cm. long; calyx-lobes about 1.5 cm. long, glabrous or 

 with scattered hairs; free tips 1.5 mm. long; petals scarcely 1.5 cm. long; capsule 

 less than 2 cm. long and scarcely 2 mm. wide. Sandy places: Wyo. Utah Ida. 

 Son. Submont. Je-Jl. 



14. A. Vreelandii Rydb. Perennial; stem erect, strict, 3-5 dm. high; 

 leaves narrowly lanceolate, about 5 cm. long, glabrous, sinuate-dentate; petals 

 about 2 cm. long, white, turning pink; pod cylindric, usually somewhat curved 

 upwards, 3 cm. long, 2 mm. thick. Hills and canons: Colo. Utah. Son. Je. 



