FLOWERING PLANTS AND FERNS OF ARIZONA 431 



25. Plants herbaceous or suffrutescent (31). 



31. Filaments all or some of them broad and flat, or dilated just 

 below the anther; flowers solitary in the leaf axils, or in 

 few-flowered umbellike clusters; leaflets few; corolla 



usually yellow 21. Lotus. 



31. Filaments all filiform or, if flat, then narrow (32). 



32. Leaves pinnatelv 3-foliolate; corolla purple or purplish (33). 

 33. Style bearded (34). 



34. Corolla 5 to 6 cm. long, lavender purple, the keel not 

 strongly curled or spirally coiled; stems erect or 

 ascending 51. Clitoria. 



34. Corolla not more than 2 cm. long, the keel strongly 



curled or spirally coiled at] apex; stems usually 



trailing or twining 56. Phaseolus. 



33. Style not bearded (35) . 



35. Stems not or barely twining; flowers solitary or in pairs 



in one axils; corolla deep red purple. 



52. COLOGANIA. 



35. Stems more or less twining; flowers in bracted racemes; 



corolla pale 54. Galactia. 



32. Leaves all or some of them with more than 3 leaflets, or 



reduced to a single leaflet, or sometimes (in Astragalus) , 



none and the rachis greatly prolonged (36). 



36. Calyx closely subtended by a pair of small, caducous 



bractlets; plants tall; leaflets numerous, linear, 



narrowly oblong, or narrowly elliptic; flowers in 



axillary racemes (37) . 



37. Plant annual; pods very long and slender, completely 



dehiscent; corolla pale yellow, usually with purple 



markings 37. Sesbania. 



37. Plant perennial with rootstocks, resembling some spe- 



cies of Astragalus; pods bladderlike, indehiscent or 

 tardily and irregularly dehiscent; corolla dull red. 



38. Swainsona. 

 36. Calyx without bractlets (38). 



38. Pods with cross partitions between the seeds, narrow, 



elongate, flat, completely dehiscent; seeds more or 

 less quadrangular in outline (39) . 

 39. Leaflets several, broad and thin; flowers several, in 



loose, long-stalked racemes; seeds not constricted; 



plants perennial 35. Cracca. 



39. Leaflet one, narrowly linear, elongate; flowers 1 or 2 



in the leaf axils, short-pediceled; seeds con- 

 stricted at the middle; plant annual. 



36. Sphinctospermum. 

 38. Pods without cross partitions; seeds commonly 

 rounded, often reniform, quadrangular in a few 

 species of Astragalus (40) . 



40. Sutures of the pods not introverted, the pods com- 



pletely 1-celled, flat, 10 or more times as long as 

 wide (41). 

 41. Stipules not spinescent; lateral veins of the leaflets 

 conspicuous 29. Tephrosia. 



41. Stipules spinescent; lateral veins inconspicuous or 



obsolete 30. Peteria. 



40. Sutures one or both of them introverted, the pods 

 often more or less completely 2-celled, less 

 (usuallv much less) than 10 times as long as wide 

 (42). 



42. Keel not beaked or, if so, then the plant caulescent 



and the stems decumbent or prostrate. 



39. Astragalus. 

 42. Keel with a prominent, erect or ascending beak; 

 plants acaulescent, the scapes erect or ascend- 

 ing 40. Oxytropis. 



286744° — 42 28 



