4o0 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



19. Leaflets several, large; stipels subulate, caducous; corolla 



of one petal, this dark violet; stamens united at 



base 25. Amorpha. 



18. Petals 5 (20). 



20. Stamens 5; plants herbaceous; flowers in dense cylindric 



spikes; corolla white, pink, or purplish. 



28. Petalostemtjm. 

 20. Stamens 9 or 10 (21). 



21. Plant shrubby; leaflets numerous, with subulate stipels; 

 flowers in elongate spikelike racemes; corolla white; 

 style bearing a large sessile gland near the apex; 

 pods thin, flat, long-exserted from the calyx. 



26. Eysenhardtia. 

 21. Plants small herbs to large shrubs, when shrubby the 

 corolla not white; leaflets few or numerous, without 

 stipels or these mostly glandlike; flowers in loose or 

 dense heads, spikes, or racemes; style not gland- 

 bearing; pods turgid, included in the calyx, or 

 long-exserted in a few shrubby species. 



27. Dalea. 

 14. Leaves not glandular-punctate (22). 



22. Margins of the leaflets denticulate to serrate, rarely entire in 

 Trifolium; leaves 3-foliolate; plants herbaceous (23). 



23. Pods scythe-shaped to spirally coiled 18. Medicago. 



23. Pods straight or nearly so (24). 



24. Flowers in elongate rather loose racemes; corolla yellow or 

 white; plants strongly aromatic when dry. 



19. Melilottjs. 

 24. Flowers in heads or short dense spikes; corolla white, pink, or 



purple; plants not noticeably aromatic when dry. 



20. Trifolium. 

 22. Margins of the leaflets entire (25). 



25. Plants shrubby or arborescent (26). 



26. Leaves 3-foliolate ; corolla about 5 cm. long, scarlet ; banner petal 

 narrow, strongly keeled, much longer than the other petals; 

 pods very large, coriaceous; seeds bright red. 



53. Erythrina. 



26. Leaves multifoliolate; corolla much less than 5 cm. long, not 



scarlet; banner petal not strongly keeled, not much longer 



than the other petals; pods not very large, not coriaceous; 



seeds not bright red (27) . 



27. Calyx in bud closely subtended by 2 caducous bractlets; 



corolla yellowish; outer wall of the pod separating from 



the inner wall; plant a low shrub 33. Diphysa. 



27. Calyx without bractlets; corolla purple, pink, or white; 



outer wall of the pod not separating from the inner wall 



(28). 



28. Herbage with malpighiaceous hairs (hairs attached at the 



middle) ; pods subglobose, 1 -seeded, very tardily 



dehiscent; plant a low shrub; leaflets numerous. 



22. Indigofera. 



28. Herbage without malpighiaceous hairs; pods elongate, 



several-seeded, rather promptly dehiscent; plants 



large shrubs or small trees (29) . 



29. Inflorescence not glandular; leaflets not cuspidate; 



plant a small tree; corolla purple and white, about 



12 mm. long; pods torulose 32. Olneya. 



29. Inflorescence glandular; leaflets cuspidate (30). 



30. Corolla 20 to 25 mm. long, purplish pink; pods not 

 torulose, hispid and usually glandular. 



31. Robinia. 

 30. Corolla not more than 15 mm. long, white or tinged 

 with pink; pods torulose, puberulent. 



34. Coursetia. 



