FLOWERING PLANTS AND FERNS OF ARIZONA 429 



Anthers not sharply differentiated, all of approximately the same size or, if 



sharply differentiated {Glycyrrhiza, Stylosanthes, Zornia), then the pods 



prickly, or else the inflorescence conspicuously bracted, the corolla 



yellow, and the pods jointed or ending in a hook (5). 



3. Rachis of the leaf extended into a simple or forked tendril, this, in Lathyrus, 



sometimes reduced to a soft bristle, or rudimentary; plants herbaceous; 



stems weak; leaves pinnate with several leaflets; corolla purple, pink, 



or whitish (6) . 



6. Style with a tuft of hairs on the back or all around, just below the 



stigma; stamen tube oblique at apex 49. Yicia. 



6. Style hairy along the inner side only, with no apical tuft; stamen tube 



not oblique 50. Lathyrus. 



>. Rachis of the leaf not ending in a tendril, but greatly prolonged in place of 

 a terminal leaflet in certain species of Astragalus (7). 



7. Fruit doment) of several indehiscent 1 -seeded segments, these often 



separating at maturity, or, it reduced to 1 seed-bearing segment, 

 then ending in a wing (Xissolia), or a hook (Stylosanthes), or the 

 plant a spiny shrub (8). 

 ( Jorolla pink or purple, exceptionally white (9). 



9. Plant an intricately branched, spiny, glabrous shrub; leaves small, 

 unifoliolate; fruit of 1 to 3 segments, these not separating at 



maturity 43. Alhagi. 



9. Plants herbaceous above ground or suffrutescent, not spiny; leaves 

 pinnately compound, sometimes reduced to one leaflet in 

 Desmodintn (10). 



10. Leaflets more than 3, without stipels 42. Hedysarum. 



10. Leaflets 1 or 3, with stipels 48. Desmoditjm. 



8. Corolla yellow or orange (11). 



11. Anthers all alike; inflorescences not conspicuous!}* bracteate, few- 

 flowered, axillary (12). 

 12. Stems twining or prostrate, often suffrutescent; leaflets usually 

 5, rather large, ovate or ovate-lanceolate; segments of the 

 fruit 1 to 3, the terminal one-winged 44. Xissolia. 



12. Stems erect; leaflets many, small, linear; segments of the fruit 



commonly more than 3, all alike 45. Aeschtnomene. 



11. Anthers conspicuously different, some large and basifixed, others 

 very small and versatile; inflorescences conspicuously bracteate; 

 plants herbaceous; stems decumbent to erect (13). 



13. Leaves 3-foliolate; bracts of the inflorescence not valvelike, 



often 3-foliolate, sharply cuspidate; fruit 1- or 2-jointed, 



tipped by the hooked persistent style 46. Stylosaxthes. 



13. Leaves 2-foliolate; bracts valvelike, a closely appressed pair 

 partly hiding each flower, entire, conspicuously veined, not 

 sharply cuspidate; fruit several-jointed, without a hooked 



tip 47. Zorxia. 



7. Fruit not segmented, but sometimes constricted between the seeds (14). 

 14. Leaves (and usually the calyx) glandular-punctate, sometimes 

 obscurely so (15). 

 15. Stems trailing or twining; flowers few, in axillary racemes or fas- 

 cicles; corolla bright yellow; pods completely dehiscent, strongly 



compressed; leaves pinnately trifoliolate 55. Rhtnchosia. 



15. Steins erect or ascending; flowers numerous, in mostly terminal 



racemes or spikes; corolla not bright yellow, sometimes oc-hro- 



leucous or pale yellow; pods not or very tardily dehiscent (16). 



16. Pods prickly; plant a tall, leafy-stemmed herb; leaves pinnate 



with numerous leaflets; flowers in dense spikelike racemes; 



corolla whitish 41. Glycyrrhiza. 



16. Pods not prickly (17). 



17. Ovule solitary; plants perennial herbs; leaves digitately 3- 



foliolate to 5-foliolate 23. Psoralea. 



17. Ovules 2 or more; leaves mostly pinnate with several or many 

 leaflets, seldom digitately trifoliolate (18). 

 18. Petals none or only one; plants shrubby; leaves pinnate with 

 numerous leaflets, these stipellate; flowers in elongate 

 spikelike racemes (19). 

 19. Leaflets very numerous, small; stipels glandular, per- 

 sistent; corolla none; stamens separate, attached at 

 base to the calvx 24. Parryella. 



