260 NORTH AMERICAN FLORA [Volume 24 



3. Homalobus brachycarpus Nutt.; T. & G. Fl. N. Am. 



1: 352. 1838. 



Astragalus simplklfoliiisS. Wats. Bot. King's Expl. 77. 1871. Not A. simplicifolius A. Gray. 1864. 

 An acaulescent perennial, with a densely tufted cespitose caudex, unifoliolate or rarely 

 3-foliolate, 1-3 em. long, silky-canescent; stipules scarious, ovate, pubescent; blades or leaflets 

 oblanceolate or spatulate, 2-3 mm. broad, acute or the earlier ones obtuse; peduncles 2-5 cm. 

 long, 3-7-flowered; bracts lanceolate or ovate, scarious, shorter than the calyx; calyx silky- 

 canescent, the tube 2 mm. long, the teeth subulate, about as long; corolla bluish-purple, similar 

 to that of H. caespitosus, but smaller, 6-8 mm. long; pod oblong, abruptly acute, 6-8 mm. 

 long, 3 mm. wide, strigose; seed 2-2.5 mm. long, scarcely 1.5 mm. wide. 



Type locality: Hills of the Platte, towards the Rocky Mountains [Wyoming). 

 Distribution: Wyoming, northern Colorado, and northeastern Utah. 



Illustrations: S. Wats. Bot. King's Expl. pi. 12, f. 3-9; M. E. Jones, Contr. W. Bot. 10: pi. 

 1; Rev. Astrag. pi. 5,f. 14 (all as A. simplUifolius). 



4. Homalobus uniflorus Rydb. Bull. Torrey Club 34: 49. 1917. 



An acaulescent perennial, with a cespitose tufted caudex; leaves unifoliolate, tufted at the 

 end of its branches, 1-3 cm. long, 1-3 mm. wide, silky-canescent; stipules scarious, ovate or 

 lanceolate, pubescent, free ; leaf-blades oblanceolate, acute, tapering below into narrow petioles ; 

 bracts filiform-subulate, usually as long as or longer than the flowers; calyx canescent, the tube 

 campanulate, 2 mm. long, the teeth subulate, about the same length; corolla dark bluish- 

 purple ; banner 8 mm. long ; wings about the same length, the blade obliquely oblong-lanceolate, 

 rounded at the apex, with an acute basal auricle, the claw half as long as the blade; keel-petals 

 shorter, the blade broadly lunate, almost semicircular, rounded at the apex and with a rounded 

 basal auricle; pod lanceolate, 5-8 mm. long, 2.5-3 mm. wide, tapering at each end, strigose; 

 seeds obliquely oblong, 2 mm. long, 1 mm. wide. 



Type locality: Evanston, Wyoming. 

 Distribution: Uintah County, Wyoming. 



5. Homalobus simplicifolius (Nutt.) Rydb. Bull. Torrey Club 



40: 52. 1913. 



Phaca simplicifolia Nutt.; T. & G. Fl. N. Am. 1: 350. 1838. 

 Astragalus simplicifolius A. Gray. Proc. Am. Acad. 6: 231. 1864. 

 Tragacantha simplicifolia Kuntze. Rev. Gen. 948. 1891. 



An acaulescent perennial, with a cespitose, densely tufted caudex; leaves densely crowded 

 at the ends of its branches; stipules thin, membranous, pubescent, ovate, erose, 3-4 mm. long, 

 free; leaves unifoliolate, 5-20 mm. long, 1-2 mm. wide, narrowly linear-oblanceolate, somewhat 

 conduplicate or involute, silvery-canescent, acute; peduncles 3-10 mm. long, 1- or 2-flowered; 

 bracts subulate; calyx-tube campanulate, 2.5-3 mm. long, more or less pubescent, the teeth 

 subulate, 1-1.5 mm. long; corolla ochroleucous; banner oblanceolate, with a broad claw; wings 

 slightly shorter, the blade lunate, with an acute basal auricle, the claw slender, two-thirds as 

 long as the blade; keel-petals 5 mm. long, the blade broadly lunate, rounded at the apex, and 

 with a rounded basal auricle, the claw broad, nearly as long as the blade ; pod glabrous, according 

 to the original description "somewhat triquetrous, longer than the calyx," obovate in cross- 

 section. 



Type locality: Rocky Mountains towards the sources of the Platte [Wyoming]. 

 Distribution: Dry hills, southern Wyoming and Colorado. 



6. Homalobus lingulatus (Sheldon) Rydb. Bull. Torrey Club 



40: 52. 1913. 



Astragalus lingulatus Sheldon, Minn. Bot. Stud. 1: 118. 1894. 

 Astragalus exilifolius A. Nels. Bull. Torrey Club 26: 10. 1899. 

 Homalobus exilifolius Rydb. Bull. Torrey Club 40: 52. 1913. 



An acaulescent perennial, with a deep-seated large root and a densely tufted cespitose 

 caudex; leaves unifoliolate, densely crowded, blackening in drying; stipules scarious, free, 5 mm. 



