FABACEAE. 211 



Pod over 1.2 cm. long. 



Pod 2-2.5 cm. long; corolla ochroleucous. 5. P. Candolleana. 



Pod 12-15 mm. long; corolla purple. 6. P. cerussata. 



Pod 3-12 mm. long. 



Pod ovoid ; plant 3-6 dm. high ; raceme many-flowered. 



7. P. Bodinii. 



Pods ellipsoid ; plant usually less than 3 dm. high ; raceme few-flowered. 

 Plant cespitose ; stem slender, 12 dm. high, slender ; leaflets 0.51 cm. 



long. 8. P. pauciflora. 



Plant pulvinate-cespitose, almost stemless ; leaflets minute. 



9. P. humillima. 



Upper suture of the pod straight or curved upwards, acute ; pod in cross-section 

 obovate. 10. P. elatiocarpa. 



1. Phaca Eastwoodiae (Jones) Rydb. (Astragalus Preussii sulcatus 

 Jones; A. Eastwoodiae Jones) In Utah and Colo. Westwater. 



2. Phaca longifolia (Pursh) Nutt. (A. pictus filifolius A. Gray) On 

 sandy soil from S. D. and Wyo. to Colo, and N. M. Salida ; Manitoti ; Mani- 

 tou Junction. 



3. Phaca picta A. Gray. (A. pictus foliosus A. Gray) In sandy soil from 

 Colo, and Utah to N. M. Denver; Colorado Springs. 



4. Phaca artipes (A. Gray) Rydb. (Astragalus artipes A. Gray) In the 

 mountains of Colo. Alt. 7000-8000 ft. Cerro Summit; Cedar Edge; Leroux 

 Creek. 



5. Phaca Candolleana H. B. K. (Astragalus triilorus A. Gray) In dry 

 places from Colo, to N. M. and Calif.; also Mex. Canon City. 



6. Phaca cerussata (Sheld.) Rydb. (Astragalus cerusatus Sheld.) Moun- 

 tain sides in Colo. Canon City, Fremont Co. 



7. Phaca Bodinii (Sheld.) Rydb. (Astragalus Bodinii Sheld.) In val- 

 leys from Mont, to Neb. and Colo. Alt. 4000-5000 ft. North Park, Larimer 

 Co. 



8. Phaca pauciflora Nutt. (A. lefrtaleus A. Gray) In the mountains of 

 Colo. Alt. 7000-10,000 ft. Mt. Harvard; North Park, Larimer Co.; Como, 

 South Park; Gunnison; Laramie River. 



9. Phaca humillima (A. Gray) Rydb. (A. humillimus A. Gray) On arid 

 table-lands of Colo. Mesa Verde, near Mancos River. 



10. Phaca elatiocarpa (Sheld.) Rydb. (Astragalus lotiHorus brachypus 

 A. Gray; A. elatiocarpus Sheld.) On plains from Minn, to Ass. to Mo., 

 Tex. and Calif. Canon City; Colorado Springs. 



11. Phaca Wetherillii (Jones) Rydb. (Astragalus Wetherillii Jones) 

 Dry hills and mesas of Colo. Grand Junction. 



26. OROPHACA Britton. 



Densely cespitose; flowers 8-10 mm. long; inflorescence not exceeding the leaves. 



Flowers about 10 mm. long; pods puberulent. i. O. tridactylica. 



Flowers about 8 mm. long ; pods hoary. 2. O. aretioides. 



Broadly cespitose with prostrate branches; flowers about 6 mm. long; peduncles 



usually exceeding the leaves ; pods hoary. 3. O. sericea. 



i. Orophaca tridactylica (A. Gray) Rydb. (Astragalus tridactylicus A. 

 Gray) On plains and hills of Colorado. Alt. 5000-6000 ft. Livermore ; 

 St. Vrain's Canon; Ft. Collins; plains near Denver; foot-hills west of Ft. 

 Collins; east of Black's Lake; near New Windsor. 



