626 MISC. PUBLICATION 423, U. S. DEPT. OF AGRICULTURE 



16. Plants perennial or biennial; basal leaf blades smaller and nar- 

 rower; capsules not woody (17). 

 17. Upper portion of the plant conspicuously pilose with long 

 spreading hairs; hypanthium 3 to 5 cm. long; sepals 2 to 3 

 cm. long; capsules quite erect, 2 to 3 cm. long. 



8. O. NEOMEXICANA. 



17. Upper portion of the plant not conspicuously pilose with long 

 spreading hairs or, if so, then also pallid with fine appressed 

 hairs; hypanthium 1.5 to 3.5 cm. long; capsules spreading, 

 deflexed, or coiled (18). 

 18. Plants essentially glabrous; capsules usually contorted; an- 

 thers 5 to 10 mm. long ~9. O. PALLIDA. 



18. Plants canescent to hoary; capsules spreading or curved, 

 sometimes contorted; anthers 3 to 6 mm. long (19). 

 1 9. Underground system a running rootstock. 



10. O. RUNCTNATA. 



19. Underground system a taproot 11. O. trichocalyx. 



1. Stigma capitate, discoid, or 4-toothed; flowers mostly diurnal (20). 

 20. Hypanthium about 1 mm. long, lined with a lobed, orange disk; stigma 

 capitate ; capsules linear, often strongly refracted ; seeds with purple dots : 



Subgenus Eulobus 20. O. leptocarpa. 



20. Hypanthium usually longer, not lined with a disk; seeds not purple dotted 

 (21)/ 

 21. Stigma discoid, somewhat shallowly 4-lobed; flowers yellow (22). 



22. Tube of the hypanthium 5 to 15 mm., long; stamens of 2 lengths; sepals 

 distinctly keeled especially toward the tip: Subgenus Calylophis. 



24. O. SERRULATA. 



22. Tube of the hypanthium 25 to 50 mm. long; stamens subequal; sepals 



not keeled: Subgenus Salpingia (23). 



23. Plants densely strigose, with a peculiar olive-gray-green color, low 



and densely tufted, 5 to 20 cm. high; leaves typically 5 to 15 mm. 



long; petals 13 to 22 mm. long; sepals 7 to 8mm. long, with free 



tips 1 to 2 mm. long 21. O. Lavandulae folia. 



23. Plants greenish or, if grayish, then with longer leaves, not so densely 

 tufted, often quite woody, 10 to 40 cm. high (24). 

 24. Stems subglabrous to minutely glandular-pubescent; leaf margins 



not crisped or wavy 22. O. hartwegii. 



24. Steins conspicuously pubescent or even pilose ; leaf margins tending 



to be crisped or wavy 23. O. greggii. 



21. Stigma capitate; flowers yellow or white (25). 



25. Capsule cylindric or tapering toward the tip, sessile or nearly so: Sub- 

 genus Sphaerostigma (26). 

 26. Flowers yellow, often drying greenish, borne in the axils of the foliage 

 leaves (27). 

 27. Cauline leaves linear to lance-linear, 1 to 3 mm. wide; petals 2 to 3 

 mm. long; capsules not 4-angled 29. O. contorta. 



27. Cauline leaves broadly lanceolate, 5 to 10 mm. wide; petals 3 to 7 



mm. long; mature capsules 4-angled 30. O. micrantha. 



26. Flowers white, often drying pinkish, borne in terminal spikes (28). 



28. Capsules terete, cylindric, linear, not thickened in the lower 



portion, scarcely if at all coiled, not noticeably attenuate at 



tip (29). 

 29. Petals 5 to 7 mm. long, suborbicular; style exceeding the 

 corolla; h}^panthium 4 to 6 mm. long; capsules refracted or 

 spreading, occasionally coiled 25. O. refracta> 



29. Petals 3 mm. long, spatulate; style shorter than the corolla; 



hypanthium 2.5 to 3 mm. long; capsules divaricately spread- 

 ing 26. O. chamaenerioides. 



28. Capsules not strictly cylindric, somewhat enlarged at base and 

 attenuate at tip, curved or bent (30) . 



30. Leaves chiefly basal, subglabrous, lance-ovate to oblanceolate; 



stems glabrous or nearly so, the epidermis exfoliating 

 promptly; capsule 15 to 25 mm. long__27. O. decorticans. 

 30. Leaves well distributed, glandular-pubescent to glandular-villous, 

 ovate to oblong-ovate; stems glandular-pubescent to gland- 

 ular-villous, the epidermis exfoliating tardily, if at all; cap- 

 sule 10 to 15 mm. long . 28. O. boothii. 



