PEA FAMILY 487 







Calyx-teeth subulate, fully as long as the tube. 



Plant appressed-pubescent, cespitose and much branched. 

 Stem ascending. 



Inflorescence scarcely equalling the leaves; pod 2-2.5 cm. 

 long; corolla ochroleucous. 15. P. Candolleana. 



Inflorescence exceeding the leaves; pod 12-15 mm. long; 



corolla purple. 16. P. cerussata. 



Stem decumbent. 17. P. serpens. 



Plant with short spreading pubescence; stem simple, elongate. 



18. P. Silerana. 

 Pod 8-12 mm. long. 



Stem slender and much branched, usually more than 1 dm. high; leaflets more 



than 5 mm. long, flat, oblong, oval, or obovate. 

 Leaflets 5-11 pairs. 



Plant slightly strigose. 



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



19. P. Bodinii. 



Pod ellipsoid; plant usually less than 3 dm. high; racemes few- 

 flowered. 20. P. leptalea. 

 Plant densely hirsutulous. 18. P. Silerana. 

 Leaflets 4-6 pairs; plant more or less grayish-pubescent; pod globose-ovoid. 



21. P. microcystis. 



Stem densely pulvinate-cespitose, with a thick caudex, only a few centimeters 



high; leaflets minute, linear or lanceolate, conduplicate, 1-4 mm. long. 



Rachis of the leaves not spinose; pod slightly puberulent, mottled, 1 cm. 



long. 22. P. jejuna. 



Rachis of the leaves spinose; pod white-pubescent, 4-6 mm. long. 



23. P. humilHma. 

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



triangular-obovate, or slightly cordate. 

 Plant, including the pods, perfectly glabrous, 2 dm. high or more; pods stipitate, 



somewhat leathery. 



Corolla ochroleucous ; calyx-teeth nearly equalling the tube. 24. P. Beckwithii. 

 Corolla purple; calyx-teeth much shorter than the tube. 25. P. artemisiarum. 

 Plant, including the pods, more or less hairy; pods sessile. 

 Pods much over 1 cm. long, usually not mottled. 



Pods strongly inflexed; flowers white or ochroleucous, tinged with purple. 



26. P. pubentissima. 



Pods not strongly incurved; upper suture straight or nearly so; flowers ochro- 

 leucous. 

 Plant strictly annual. 



Plant cinereous, with short hairs; pods puberulent. 27. P. annua. 

 Plant, including the pods, grayish hoary. 28. P. sabulonum. 



Plant perennial or at least biennial, cespitose, low. 



Flowers mostly subsessile in the axils of the leaves; racemes if ped- 

 uncled 2-3-flowered ; leaflets mostly over 1 cm. long, appressed-hairy . 



29. P. elatiocarpa. 

 Flowers in peduncled several-flowered racemes ; leaflets mostly less than 



1 cm. long, loosely hairy beneath, glabrate above. 30. P. lotiflora. 

 Pods about 1 cm. long, mottled; plant diffusely cespitose. 31. P. sesquiflora. 



1. P. americana (Hook.) Rydb. Perennial; stems single or two or three, 

 erect, 3-10 dm. high; leaflets 7-17, oval, elliptic, or oblong, obtuse, thin, 2-4 cm. 

 long, glabrous above, sparingly pubescent beneath; raceme short; calyx glabrous 

 or nearly so; tube campanulate, 4 mm. long; teeth obsolete; corolla ochroleucous, 

 about 12 mm. long; pod glabrous; stipe about 5 mm. long; body ellipsoid, acute, 

 2 cm. long, 7-8 mm. wide. Astragalus frigidus americanus S. Wats. Along 

 streams and in wet copses: Que. Wyo. Yukon. Submont. Mont. Jl-Au. 



2. P. ampularia (S. Wats.) Rydb. Perennial; stem short, ascending, 

 strigose; leaflets 7-11, obovate, 8-12 mm. long, emarginate, glabrous above, 

 strigose beneath; racemes short and dense; calyx-tube cylindro-campanulate, 

 5-6 mm. long; teeth nearly obsolete; banner 15-18 mm. long; pod oblong, on a 

 long stipe, glabrous. Astragalus ampullarius S. Wats. Wet places: s Utah. 

 L. Son. Ap-My. 



3. P. Wetherillii (M. E. Jones) Rydb. Cespitose perennial; stems ascend- 

 ing, 3-4.5 dm. long, glabrous or sparingly strigose above; leaflets 9-17, oval or 

 obovate, rounded or retuse at the apex, 8-10 mm. long, glabrous; inflorescence 

 6-8-flowered; calyx-tube campanulate, 3 mm. long; teeth subulate, 2 mm. long; 

 corolla white, tipped with pink, 8 mm. long; body of the legume ovoid, about 2 

 cm. long, sulcate above, puberulent. A. Wetherillii M. E. Jones. Dry places: 

 Colo. Son. My. 



4. P. allochroa (A. Gray) Rydb. Perennial; stem 1-3 dm. high, strigose, 

 ascending; leaves 5-10 cm. long; leaflets 13-15, oblong, strigose, obtusish, 8-10 



