PEA FAMILY 491 



31. P. sesquiflora (S. Wats.) Rydb. Cespitose perennial; stems 1 dm. or 

 less long, silky strigose-canescent; leaflets 5-11, linear-lanceolate, strigose-canes- 

 cent, 5-8 mm. long; racemes 1-2-flowered; cal>TC-tube 2.5 mm. long; teeth subu- 

 late, 2.5 mm. long; corolla purple, about 7 mm. long; pod about 1 cm. long, 4 

 mm, broad, minutely strigose, mottled, somewhat curved. A, sesqnifloms S. 

 Wats. Dry hills: s Utah. L. Son. Je. 



19. CYSTIUM Stev. 



Cespitose perennials, with branched rootstocks. Leaves alternate, odd- 

 pinnate, with several pairs of leaflets, most commonly glabrous or sparingly 

 pubescent. Stems mostly decumbent or prostrate, rarely ascending or erect. 

 Flowers white or purplish, in rather few-flowered spikes. Calyx short-cylindric 

 or campanulate; teeth mostly subulate. Pods membranous, much inflated, 

 ovoid, ellipsoid, or globose, perfectly 2-celled by the intrusion of both sutures, 

 several-seeded. 



Plant cespitose, less than 1 dm. high, canescent, nearly stemless; pod- not curved. 



1. C. platytrope. 

 Plant with elongate stems, 1-4 dm. high. 



Plant silvery canescent-strigose ; corolla pinkish. * ' 2. C CouUeri. 



Plant glabrous or slightly strigose, not silvery. 



Corolla purple. . 3. C diphysum. 



Corolla white or yellowish, purple only at the tip. 

 Pod more than 1.5 cm. long. 



Pod short-ovoid, only slightly curved. 4. C. heliophilum. 



Pod elongate-ovoid, strongly curved. 



Calyx-teeth at least half as long as the tube; corolla 8-9 mm. long. 



5. C. leniiginosum. 

 Calyx-teeth about one-fourth as long as the tube; corolla about 12 mm. 

 long. 6. C. araneosum. 



Pod 1-1.5 cm. long. 7. C. salinum. 



1. C. platytrope (A. Gray) Rydb. Stems 1-3 cm. long; leaves crowded at 

 the base; leaflets 7-11, obovate or oblanceolate, 5-10 mm. long; spike fevr- 

 flowered, capitate; calyx strigose; tube 3 mm. long; teeth subulate, 2 mm. long; 

 corolla white or yellowish, tipped with purple, 7 mm. long; pod ovoid, 2 cm. long, 

 sessile, cinereous-puberulent, mottled. Astragalus plaiytropis A. Gray. Moun- 

 tains: Nev.— Mont. MonL Jl. 



2. C. Coulteri (Benth.) Rydb. Stem 3-4 dm. high, white silky-strigose, 

 branched; leaflets 9-19, broadly obovate, 8-15 mm. long, roxmded or retuse at 

 the apex; spike lax; calyx-tube about 5 mm. long; teeth lance-subulate, 2 mm. 

 long; corolla about 12 mm. long; pod ovoid, cinereous-strigose, about 2 cm. long. 

 A. CouUeri Benth. Arid regions: s Utah — Ariz. — s Calif. F-Ap. 



3. C. diphysum (A. Gray) Rydb. Stems ascending or decumbent, 2-4 dm. 

 high; leaflets 19-21, oblong or elliptic, glabrous, fleshy, rounded or retuse at the 

 apex, 6-10 mm. long; spike dense, oblong; calyx glabrous; tube 5-6 mm. long; 

 teeth subulate, 2 mm. long; corolla 15 mm. long; pod ovoid, acuminate, and 

 somewhat incurved at the apex, about 2 cm. long, glabrous, somewhat sulcate 

 on both sutures. A, diphysus A. Gray. Hills: N.M. — Colo. — Utah— Ariz. 

 Son, My-Jl. 



4. C. heliophilum Rydb. Perennial, with a deep taproot and a short cespi- 

 tose caudex; stems decumbent or ascending, sparingly strigose, 1-4 dm. high; 

 leaflets rather fleshy, light green, obovate, sparingly strigose, 7-10 mm. long, 

 rounded, retuse or emarginate at the apex; raceme short, oblong; calyx strigose; 

 tube about 5 mm. long; teeth lance-subulate, 2-3 mm. long; corolla ochroleucous, 

 12-14 mm. long; pod ovoid, acute, somewhat sulcate on both sutures, about 2 

 cm. long, 1 cm. in diameter, short-acuminate. Phaca inepta Rydb., in part. 

 Astragalus ineptus Coult. & Nels. Hills and mountain sides: Mont. — Wyo. — 

 Utah. SubmonL My-Jl. 



5. C- lentiginosum (Dougl.) Rydb. Stems decumbent or diffusely spread- 

 ing; leaflets 11-19, obovate or obcordate to elliptic, 8-12 mm. long, slightly 

 strigose or glabrate; raceme short and dense; calyx strigose; tube 3-4 mm. long; 

 teeth subulate, 2 mm. long; corolla ochroleucous or white, 8-9 mm. long; pod 



