WOOTON AND STANDLEY—FLORA OF NEW MEXICO. 311 
KEY TO THE SPECIES. 
Annuals or biennials with very leafy many-flowered cymes. 
Achenes with a corky gibbosity on the upper suture; leaves 
pinnate, with 4 or 5 pairs of leaflets....-..--.-..-+--- 1. P. paradoxa. 
Achenes not gibbous; leaves pinnate or digitate. 
Lower leaves pinnate, with 2 approximate pairs of 
leaflets.........22. 20-2 eee eee eee eee eee eee eee 2. P. rivalis. 
Leaves all digitate. 
Petals about half as long as the sepals; achenes 
smooth; hypanthium in fruit 5 mm. wide or 
less; stamens 10..........----2----2--- eee 3. P. millegrana. 
Petals equaling the sepals or nearly so; achenes 
rugulose; hypanthium about 7 mm. wide; 
stamens 15 to 20. 2.2... eee ee ee eee eee ee eee 4, P. monspeliensis. 
Perennials with few-flowered, not very leafy cymes. 
Flowers red. 
Leaves green above, white-tomentose beneath.........- 5. P. atrorubens. 
Leaves glabrate or silky beneath, without tomentum.... 6. P. thurberi. 
Flowers yellow. 
Leaves digitate. 
Plants glabrous throughout. .........-..++++---+-- 7. P. sierrae-blancae. 
Plants abundantly pubescent. 
Plants tall, more than 20 cm. high..........-.-11. P. filipes. 
Plants low, less than 20 cm., usually less than 
10 cm. high. 
Leaves tomentose beneath...........--.-- 10. P. bicrenata. 
Leaves not tomentose beneath. 
Stems simple, erect; sepals and bract- 
lets not incurved...............- 8. P. diversifolia. 
Stems much branched, spreading; 
sepals and bractlets incurved... 9. P. subviscosa. 
Leaves odd-pinnate. 
Style not longer than the mature achene, thickened 
at the base; leaflets deeply lobed into narrow 
oblong teeth.........--.-------+--2 2-2 eee eee 12. P. strigosa. 
Style much longer than the mature achene, filiform; 
leaflets not lobed, merely coarsely toothed or 
nearly entire. 
Leaves green on both sides, or merely strigose. 
Pedicels arcuate-spreading in fruit......... 19. P. plattensis. 
Pedicels erect. 
Stems stout, 60 to 70 cm. high; leaflets 
obovate-oblong, coarsely serrate.13. P. ambigens. 
Stems 10 to 40 cm. high, slender; 
leaflets cuneate or linear-oblong, 
toothed only at the apex. 
Stems ascending or decumbent; 
leaflets conduplicate; pistils 
mnumerous.......-.--------- 14. P. crinita. 
Stems erect; leaves flat; pistils 5 
to 12.2.2... 2. eee eee ee eee 15. P. lemmont. 
Leaves tomentose beneath. 
Leaves almost equally white-pubescent on 
both surfaces. ..........2-2-------- 16. P. hippiana. 
