EVENING-PRIMROSE FAMILY 597 



15. A. cinerea Rydb. Branched perennial; stem 3-4 dm. high, cinereous- 

 strigose when young; leaves lanceolate to ovate-lanceolate, mostly subsessile, 

 3-5 cm. long, sinuate-dentate or denticulate, cinereous; tips of the calyx free 

 and rather long; petals 15-18 mm. long; pods 3-3.5 cm. long, 3 mm. thick, almost 

 straight. Dry soil: S.D. w Neb. Ida. Colo. Plain Submont. Je-Jl. 



16. A. runcinata (Engelm.) Woot. &Standl. Perennial; stem much branched, 

 2-4 dm. high, cinereous; leaves lanceolate to linear, canescent-strigose, 2-6 cm. 

 long, pinnatifid, with triangular-lanceolate, divergent lobes; tube of hypanthium 

 and calyx-lobes each 1.5-2 cm. long; free tips about 1 mm. long; petals 1.5-2 cm. 

 long; pod divergent, 3-4 cm. long, 2-3 mm. thick, often twisted. O. albicaulis 

 runcinata Engelm. Dry places: Tex.' Utah Ariz. Son. Ap-S. 



17. A. latifolia Rydb. Perennial, whole plant strigose-canescent; stem 

 divaricately branched, 2-6 dm. high; leaves ovate, oblong or lanceolate, sinuate- 

 dentate, 2-6 cm. long; tube of hypanthium and calyx-lobes about 2 cm. long; 

 free tips 1.2-2 mm. long; petals nearly 2 cm. long; capsule divaricate, usually 

 curved, 3 cm. long, 3 mm. thick. Sandy soil: Neb. Kans. Utah Ida. Plain 

 Mont. 



18. A. coronopifolia (T. & G.) Britton. Perennial, with a rootstock; 

 stem 1-3 dm. high, strigose; leaves 1-6 cm. long, pinnatifid, with linear divisions, 

 or the basal ones spatulate and merely dentate; tube of hypanthium 1-2 cm. 

 long, strigose; calyx-lobes 1.5-2 cm. long; free tips less than 1 mm. long; petals 

 1-1.5 cm. long; capsule oblong, 1-1.5 cm. long, 4 mm. thick. 0. coronopifolia 

 T. & G. Prairies and plains: S.D. Kans. N.M. Ariz. Ida. Plain Mont. 

 Je-Au. 



12. PACHYLOPHUS Spach. ROCK ROSE, MOUNTAIN PRIMROSE. 



Acaulescent or short-stemmed perennials. Leaves mostly crowded, toothed, 

 lobed, or pinnatifid. Flowers axillary, perfect, night-blooming. Hypanthium 

 much elongated beyond the ovary into a narrowly funnelform tube. Sepals 4, 

 elongate, reflexed. Petals white, turning pink, showy. Stamens 8. Stigma 

 with 4 linear lobes. Capsule lance-ovoid or ovoid-oblong, large, 4-angled, with 

 more or less wavy-crested angles, woody, tardily loculicidal. Seeds many, in 1 

 or 2 rows in each cell. 



Plant glabrous, or nearly so. 1. P- caespitosum. 



Plant hairy. 



Plant not canescent-strigose. 



Leaves lyrate-pinnatifid ; apex and lobes rounded or obtuse ; hairs with pustulate 



bases. 2. P. Johnsoni. 



Leaves sinuately lobed or toothed, acute; hairs not pustulate at the bases. 



HypantMum, calyx, and fruit glabrous, slightly strigose or with a few scattered 



long hairs. 

 Tube of the hypanthium 3-6 cm. long; pubescence short and usually ap- 



pressed. 3. P. montanus. 



Tube of hypanthium 6-12 mm. long. 



Plant acaulescent, cespitose; pod short, conic-ovoid, with very thick 



ridges. 4. P. macrogloUis. 



Plant more or less caulescent; pod elongate, conic-ovoid, with low ridges. 



5. P. caulescens. 

 Hypanthium, calyx, and fruit densely hirsute. 



Fruit subsessile, conic-ovoid, obtuse at the base. 



Plant acaulescent; ridges of the fruit slightly tuberculate. 



Hypanthium 8-12 cm. long; petals 3^1 cm. long. 6. P. hirsutus. 

 Hypanthium about 5 cm. long; petals about 2 cm. long. 



7. P. crinitus. 

 Plant more or less caulescent; ridges of the fruit with lobed, more or 



less foliaceous crests. 8. P. exirmus. 



Fruit more or less stipitate, fusiform, tapering at both ends, with slightly 

 tuberculate ridges ; plant often more or less caulescent. 9. P. marginatus. 

 Plant densely canescent-strigose throughout. 10. P. canescens. 



1. P. caespitosus (Nutt.) Raim. Cespitose acaulescent perennial; leaves 

 with winged petioles, 1-2 dm. long; blades oblanceolate, glabrous, sinuate-den- 

 tate, with triangular teeth; tube of the hypanthium 5-10 cm. long, glabrous; 

 petals 3-4 cm. long; fruit lance-ovoid, 3 cm. long, with low rounded tubercles 

 on the angles. Oenothera caespitosa Nutt. P. glabra A. Nels., a depauperate 

 form. Dry hills: Sask. Neb. N.M. Utah Mont. Plain Mont. Je-Au. 



