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 ocliroleucous. 15. P. CandoUeana. 



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 shghtly 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 gra j-ish-pubescent ; pod globose-ovoid. 



21. P. microcystis. 

 Stem densely pul\inate-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. humiUinia. 

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

 triangular-obovate, or shghtly cordate. 

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

 somewhat leathery. 

 Corolla oclu-oleucous ; calyx-teeth nearly eciualling the tube. 24. P. Beckwithii. 

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



Plant, including the pods, more or less hairj-; pods sessile. 

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



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



26. P. pubentissima. 

 Pods not stronglj- incurved; upper sutiire straight or nearly so; flowers ochro- 

 leucous. 

 Plant strictly annual. 



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

 Plant, Including the pods, graj-ish 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 m.ostly 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. loti flora. 

 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, elUptic, 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 frigidiis 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, strigosei 

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



