FLOWERING PLANTS AND FERNS OF ARIZONA 625 



Key to the species 

 Stigma with 4 linear lobes; flowers mostly vespertine (2). 



Capsule sharply 4-angled or -winged, at least in the upper part, rather short 



for its thickness; plants perennial (3). 

 3. Flowers white to red; capsule club-shaped, the lower part narrow and 

 sterile, the upper part thicker, ribbed or winged; seeds in more than 

 2 rows in each cell: Subgenus Hartmannia (4). 

 4. Buds nodding; lower sterile part of the capsule cylindric and sessile; 



petals white to pink, 2.5 to 4 cm. long 14. O. bpeciosa. 



4. Buds erect; lower sterile part of the capsule tapering toward the 

 petals 0.5 to 1.5 cm. long (5). 

 5. Petals rose, 5 to 10 mm. long; hypanthium 4 to 8 mm. long. 



15. O. rosea. 

 5. Petals white to pink, 10 to 15 mm. long; hypanthium 10 to 20 mm. 



long 16. 0. KUXTHIAXA. 



3. Flowers yellow; capsule bod}- proper ovoid or prismatic (6). 



6. Seeds in 1 row in each cell, with corky tubercles; capsule broadly 

 winged throughout its length; hypanthium 5 to 15 cm. long; petals 



3 to 5 cm. long: Subgenus Megapterium 19. O. brachycarpa. 



6. Seeds in 2 rows in each cell, granular, with a winglike margin around 



the obtuse summit; capsule winged most widely in the upper half: 



Subgenus Lavauxia (7). 



7. Tube of the hypanthium 4 to 8 cm. long; sepals and petals 1 to 2 



cm. long; wings of the capsule 2 to 5 mm. wide. _ 17. 0. flava. 



7. Tube of the hypanthium 12 to 18 cm. long; sepals and petals 3 to 4 



cm. long; wings of the capsule 1 to 2 mm. wide. 



18. O. TARAXACOIDES 



2. Capsule terete or round-angled, elongate, not winged (8). 



8. Seeds sharply angled, in 2 rows in each cell of the capsule; capsule some- 

 what cylindric or fusiform, gradually tapering upward: flowers yellow, 

 opening in the evening: Subgenus Euoenothera or Onagra (9). 

 9. Petals 10 to 14 mm. long, not very red in age; free tube of the hy- 

 panthium 2 to 4 cm. long 3. O. PROCERA. 



9. Petals 25 to 40 mm. long, reddish or purplish in age (10). 



10. Free tube of the hypanthium 3 to 5 cm. long; leaves usually distinctly 



denticulate 1. 0. hookeri. 



10. Free tube of the hypanthium 8 to 12 cm. long; leaves often almost 



entire 2. O. loxgissima. 



8. Seeds not sharply angled (11). 



11. Plants tufted or almost acaulescent: seeds with a deep furrow along 



the raphe; capsule cylindric or lance-ovoid, thick-walled, usually 



ridged, often tubercuiate: Subgenus Pachylophis (12). 



12. Flowers white, aging pink : plant perennial; sepals 25 to 35 mm. long; 



anthers 10 to 14 mm. long 12. O. caespitosa. 



12. Flowers yellow, aging red: plant annual; sepals 15 to 28 mm. long; 



anthers 5 to 10 mm. long 13. O. primivekis. 



11. Plants definitely caulescent: seeds not with a deep raphal groove (13). 



13. Capsule membranous, slightly enlarged in the upper part; seeds in 



2 rows in each cell, with shallow pits in regular rows: Subgenus 

 Raimannia (14). 

 14. Flowers yellow: buds erect: petals 5 to 15 mm. long. 



4. O.' LACIXIATA. 



14. Flowers white: buds nodding (15). 



15. Plant perennial from slender underground rootstocks; hypan- 

 thium with conspicuous white hairs in the throat : petals 7 to 

 11 mm. long; capsule 8 to 20 mm. long. 



5. O. ( OROXOPIFOLIA. 



15. Plant annual or winter annual: hypanthium not long-hairy in 

 the throat; petals 15 to 40 mm. long; capsule 20 to 40 mm. 

 long 6. O. ALBICAULIS. 



13. Capsule woody, cylindric, slightly narrowed toward the apex: seeds 

 in 1 row in each cell, not pitted; flowers white: Subgenus Anogra 



(in,. 



16. Plant a coarse spring or winter annual: basal leaf blades rhombic, 

 2 to 8 cm. long; capsules woody, 2 to 7 cm. long, with exfoliating 

 epidermis; buds often shaggy 7. O. deltoides. 



