208 FABACEAE. 



2. Diholcos decalvans (Gandoger) Rydb. (A. bisulcatus decalvans Gan- 

 doger) River valleys of Colo. Alt. about 5000 ft. New Windsor, Weld 

 Co.; Ft. Collins; Dixon Canon; Quimby. 



3. Diholcos Haydenianus (A. Gray) Rydb. (A. Haydenianus A. Gray) 

 In the mountains of Wyo. and Colo. Alt. about 7000 ft. Rio Blanco, south 

 of Pagosa; Mancos; Pagosa Springs; Montrose; La Veta; Gunnison; 

 Ridgeway. 



23. KENTROPHYTA Nutt. 



Stipules united only at the base, more or less herbaceous. 



Plants 3-4 dm. high, usually erect ; stipules with long spinulose tips. 



2. K. imp ens a. 



Plant low ; stipules not spinulose-tipped. 3. K. viridis. 



Stipules united for about half their length, scarious. 



Corolla ochroleucous, about 4 mm. long ; leaflets less than 5 mm. long. 



4. K. Wolfii. 

 Corolla purple, about 6 mm. long; leaflets over 5 mm. long. 5. K. aculeata. 



1. Kentrophyta impensa (Sheldon) Rydb. (Astragalus viridis impensus 

 Sheldon; A. Kentrophyta elatus S. Wats.) In canons and bad-lands from 

 Colo, to Nev. and Ariz. Grand River Canon. 



2. Kentrophyta viridis Nutt. (Astragalus Kentrophyta A. Gray, in part.) 

 In canons and bad-lands of Wyo. and Colo. Palisades. 



3. Kentrophyta Wolfii Rydb. (Homalobus Wolfii Rydb.) On dry hills of 

 Colo. South Park. 



4. Kentrophyta aculeata (A. Nels.) Rydb. (A. tegetarius implexus Canby; 

 A. aculeatus A. Nels.) On dry hills and mountains from Mont, to Colo, and 

 Utah. Alt. 8000-10,000 ft. Chambers' Lake; Georgetown. 



24. HOMALOBUS Nutt. 



Leaves simple or some rarely pinnately 3-foliolate ; plants pulvinate-cespitose. 



SIMPLICIFOLII. 

 Leaves pinnately 5-many-foliolate. 



Pods sessile or short-stipitate ; stipe seldom exceeding the calyx. 

 Pods more or less compressed. 



Pods oval, ovate, broadly oblong or elliptical TENELLI. 



Pods linear, 1.5 cm. or more long. CAMPESTRES. 



Pods terete or nearly so. FLEXUOSI. 



Pods long-stipitate ; stipe many times as long as the calyx. MACROCARPI. 



SIMPLICIFOLII. 

 One species. i. H. caespitosus. 



TENELLI. 

 Pods strictly sessile. 



Pods erect on long pedicels. 2. A. grallator. 



Pods spreading or reflexed on short pedicels. 



Pods glabrous; plant canescent. 3. H. Wingatanus. 



Pods hairy ; plant green. 4. H. dementis. 



Pods short-stipitate. 



Leaflets broadly linear or oblong; corolla ochroleucous. 5. H. tenellus. 



Leaflets narrowly linear ; corolla whitish, tinged with purple. 



6. H. acerbus. 



CAMPESTRES. 

 Calyx-teeth lanceolate to subulate, half as long as the tube or longer. 



Pods arcuate. 7. H. decumbens. 



Pods straight. 



