56 LEGUMINOS.E. (PULSE FAMILY.) 



heads hemispherical: involucre of 2 broadly stipuled 3-foliolate leaves: ovary 

 one-ovukd. Watson, Bot. King's Exp. 60, t. 8. W. Wyoming and N. E. 

 Utah. 



* -i Slender annuals, glabrous : lobes of ike involucre laciniately and sharply 



toothed. 



11. T. involucratum, Willd. Branching from the base : leaflets mostly 

 oblanceolate, acute at each end, spinulosely-serru/ate^. flowers in close heads, purple 

 tipped with white : calyx-teeth thin : ovules several. From Mexico to the British 

 boundary, and from Colorado and New Mexico to the Pacific. 



12. T. pauciflorum, Nutt. Very slender : stems ascending or decum- 

 bent: leaflets obovate or oblanceolate or sometimes linear, usually obtuse or 

 refuse, serrulate : heads rather few-flowered : involucre small -i. flowers little ex- 

 ceeding the calyx, deep purple or light rose-colored : ^calyx-teeth rigid, setosely 

 acuminate: ovules two. T. variegatum, Nutt., in Bot. King's Exp. and Hayd. 

 Rep. 1872. From Washington Terr, and Montana to S. California and Utah. 



5. HOSACKIA, Douglas. 



Calyx-teeth nearly equal, usually shorter than the tube. Petals free from 

 the stamens, nearly equal ; keel somewhat incurved. Pod sessile, partitioned 

 between the seeds. Herbaceous: leaves (in ours) 1 to 5-foliolate; stipules 

 minute and gland-like. Watson in Bot. King's Exp. 432. 



1. H. Wrightii, Gray. Perennial: ashy-puberulent, bushy-branched, very 

 leafy : leaflets 3 to 5, apparently palmate and sessile, the lowest oblong, the rest 

 filiform-linear: peduncles short, rarely equalling the leaf, 1 to 2-flowered : calyx- 

 teeth setaceous-subulate, about equalling the tube : keel not f alcatel y -attenuate, 

 mostly very obtuse. S. W. Colorado, New Mexico, and Arizona. 



2. H. Pu.rsh.iana, Benth. Annual: more or less silky-villous or sometimes 

 glabrous: leaves nearly sessile; leaflets 3* (or 1, rarely 4), varying from ovate to 

 lanceolate : peduncles exceeding the leaves, one-flowered : calyx-teeth linear, much 

 longer than the tube, about equalling the corolla : keel attenuated upward, falcate, 

 mostly acute. From Washington Terr, to Northern Mexico, eastward to the 

 Upper Missouri, Arkansas, and N. Carolina. 



6. PSORALEA, L. 



Two upper calyx-lobes often connate. Keel united with the wings. Sta- 

 mens mostly diadelphous. Pod sessile, thick and often wrinkled. Perennial 

 herbs : leaves (in ours) digitate, the leaflets entire; stipules not adnate to the 

 petiole : flowers white or purplish. 



* Flowers in panicled racemes. 



1 . P. tenuiflora, Pursh. Slender, much branched and bushy, minutely 

 hoary-pubescent when young : leaflets varying from linear to obovate-oblong : 

 lobes of the calyx and bracts ovate, acute : pod glandular. P. floribunda, 

 Nutt. From Texas to Arizona, northward to the Missouri River and eastward 

 into Illinois. 



