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; calyx-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. sesquiflorus 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-strigqse ; corolla pinkish. 2. C. Coulteri. 



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. lentiginosum. 

 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 few- 

 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 platytropis A. Gray. Moun- 

 tains: Nev. Mont. Mont. Jl. 



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

 branched; leaflets 9-19, broadly obovate, 8-15 mm. long, rounded 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. Coulteri 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 silicate 

 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. Submont. 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- 



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



