FABACEAE. 207 



4. Xylophacos vespertinus (Sheld.) Rydb. (A. vespertinus Sheld.) In 

 arid places of W. Colo, and N. Mex. Grand Junction. 



5. Xylophacos Shortianus (Nutt.) Rydb. {A. Shortianus Nutt.) On 

 plains and dry hills from western Neb. and Wyo. to Colo, and Ariz. Alt. 

 4000-9000 ft. Ute Pass ; plains near Denver ; Clear Creek Canon ; Ft. Col- 

 lins; Rist Canon; Spring Canon; west of Dixon Canon; Hotchkiss; Table 

 Rock ; Soldier Canon ; vicinity of Horsetooth ; Grand Junction ; north of La 

 Porte; near Boulder; Sapinero; Arboles. 



6. Xylophacos amphioxus (A. Gray) Rydb. (A. amphioxus A. Gray) 

 On dry plains and hills from southwestern Colo, to Utah and Ariz. Exact 

 locality not given. 



7. Xylophacos uintensis (Jones) Rydb. (Astragalus Uintensis Jones) 

 On dry mesas from Colo, to Utah and Ariz. Alt. 4000-7000 ft. Mancos ; 

 mesas near Pueblo ; Cimarron ; Grand Junction. 



8. Xylophacos Newberryi A. Gray. Dry hills from southwestern Colo, 

 and Utah to N. M. and Ariz. Exact locality not given. 



9. Xylophacos Purshii Dougl. On plains and hills from Mont, and B. C. 

 to northern Colo, and Calif. Along North Platte. 



19. CTENOPHYLLUM Rydb. 



i. Ctenophyllum pectinatum (Hook.) Rydb. (Phaca pectinata Hook.; 

 Astragalus pcctinatus Dougl.) On dry plains from Alb. and Sask. to Kans. 

 and Colo. Ft. Collins. 



20. CNEMIDOPHACOS Rydb. 



i. Cnemidophacos flavus (Nutt.) Rydb. (Astragalus flavus Nutt.) On 

 dry mesas from Wyo. to N. M. Alt. about 6000 ft. Grand Junction ; Man- 

 cos; Arboles. 



21. MICROPHACOS Rydb. 



i. Microphacos microlobus (A. Gray) Rydb. (Astragalus microlobus A. 

 Gray) On plains and hills from S. D. and Mont, to Kans. and Colo. Alt. 

 4000-7000 ft. Ft. Collins; Walsenburg; New Windsor; mesas near Pueblo; 

 Cucharas Valley, near La Veta; Denver; Colorado City. 



22. DIHOLCOS Rydb. 



Corolla over i cm. long ; calyx-teeth nearly as long as the tube. 



Corolla purplish or pinkish; pod strigose. i. D. bisulcatus. 



Corolla whitish ; pod glabrous. 2. D. decalvans. 



Corolla whitish or straw color, less than i cm. long ; calyx-teeth much shorter than 



the tube. 3. D. Haydenianus. 



i. Diholcos bisulcatus (Hook.) Rydb. (Phaca bisulcata Hook.; Astragalus 

 bisulcatus A. Gray) On plains and in river valleys from Sask. and Mont, to 

 Neb. and Colo. Alt. 4000-8000 ft. Pueblo; between La Veta and Gardner; 

 Ft. Collins; mesas near Pueblo; Lamar; Spring Canon; Platte River; 

 Colorado Springs. 



