198 Vniversiti) of California Puhlications in Botany [Vol. 10 



Leaf rachis scarcely if at all dilated; umbels reduced to one flower; keel 

 acute, attenuately beaked. 

 Calyx teeth shorter than the tube; legumes constricted between the 

 seeds; leaves, at least many of them, of more than 3 leaflets. 



14. L. micranthus 



Calyx teeth longer than the tube, approaching the length of the 

 corolla; legumes scarcely if at all constricted between the 

 seeds; leaves of 3 (1 to 5) leaflets 15. L. americanus. 



Seeds variable but always flattened and angled at one or both ends, a cross- 

 section through center diamond-shaped; legumes oblong to linear; 

 flowers subsessile; rachis dilated. 

 Legumes 1 to 2.5 cm. long. 



Plants erect; flowers wiiitish cream-color, tinged with purple; calyx 



teeth longer than tube 16. L. denticulatus. 



Plants not erect; flowers yellow, tinged with reddish purple; calyx 

 teeth shorter or slightly longer than the tube.... 17. L. suhpiimatus. 



Legumes not more than 1 cm. long; plant not erect; flowers yellow, 

 tinged with reddish purple; calyx teeth much longer than the tube. 

 18. L. Immistratus. 



Subgenus 3. Syrmatiuni. Mostly perennials (often flowering the 

 first season) ; leaves short-pinnate with gland-like stipules; flowers 

 2 to 12 mm. long, umbellate (umbels sometimes reduced to a single 

 flower) ; legumes small, less than 2 cm. in length, arcuate to nearly 

 straight, mostly attenuate into a long incurved beak, one to several- 

 seeded ; fruits reflexed, indehiscent, deciduous at base of pedicel. 



Annuals; legumes usually 2-seeded, more or less constricted between the seeds, 

 long and slender, slightly curved. 



Umbels pedunculate; flowers 5 to 7 mm. long; style glabrous 



19. L. nuUallianus. 



Umbels nearly sessile; flowers 3 to 4.5 mm. long; style pubescent 



20. L. hamatus. 



Perennials. 



Legumes one to several-seeded, not constricted (slightly so in L. benthamii). 

 Claws of petals exserted beyond calyx tube (except in variety of L. 

 leucopliyllus) ; floAvers in pedunculate or sessile umbels and more 

 than 5 mm. long. 



Umbels sessile or short-peduncled, ebracteate; calyx teeth erect. 



Umbels 1 to 4-flowered; legumes straight or falcate; herbage 

 appressed silky-canescent 21. L. leucophyUus. 



Umbels many to few-flowered; legumes falcate; pubescence (e.xeept 

 in var. veatchii) scanty, appressed, confined to young herbage 

 and calyces and occasionally to legumes 22. L. scoparius. 



Umbels peduncled; bract, when present, of 1 or 2 leaflets; legumes 

 falcate. 



Calyx teeth subulate, often recurved 23. L. benthamii. 



Calyx teeth short subulate-triangular.. ..22. L. scoparius var. traskiae. 



Claws of petals not exserted beyond calyx tube; flowers mostly solitary 

 and not over G mm. long 24. L. haydonii. 



