142 Order ROSALES 
1. Orophaca cespitosa (Nutt.) Britton. 
Dry hills in the western part of the state. Banner county; Bel- 
mont; Ft. Robinson; Kimball county. 
2. Orophaca argophylla (Nutt.) Rydb. 
In dry soil in the western part of the state. Cheyenne county; 
Deuel county. 
3. Orophaca sericea (Nutt.) Britton. 
In dry, sandy or rocky places in the western part of the state. Alli- 
ance; Belmont. 
16. Astragalus. 550. 
Milk Vetches. 
Pods one-celled, one or both sutures intruded in some, but not form- 
ing a complete partition. 
Pods with two deep grooves on the upper side, stipitate; plants 
erect; flowers deep purple. 8. A. bisulcatus. 
Pods not two-grooved on the upper side. 
Flowers purple, violet or blue; pods not cordate in cross section. 
Plants low, tufted, silvery canescent. 
Stems short; pods straight, circular in cross section. 
1. A. missouriensis. 
Acaulescent; peduncles mostly shorter than the leaves; pods 
curved. 2. A. shortianus. 
Plants with slender, mostly erect stems. 
Flowers 6-8 mm. long; pods less than a cm. long. 
3. A. gracilis. 
Flowers larger; pods 15-25 mm. long. 4. A. flexuosus. 
Flowers yellow or yellowish-white, the keel in some tinged with 
purple. 
Pods not cordate in cross section, sessile in the calyx. 
Stems 3-6 dm. high; leafiets linear; pods glabrous. 
5. A. pectinatus. 
Nearly acaulescent, pubescent with long white hairs; pods 
villous-pubescent. 6. A. lotiflorus. 
Pods distinctly cordate in cross section, stipitate. 
Pods about 2-5 cm. long, almost triangular in cross section. 
9. A. racemosus. 
Pods about 5 em. long; calyx dark pubescent. 
10. A. drummondii. 
Pods two-celled, sutures intruded and forming a complete partition. 
Pods not fleshy, dehiscent. 
Flowers yellow; plants erect. 11. A. carolinianus. 
Flowers violet or purple. 
Stems very short; pods grooved on both sutures, densely vil- 
lous pubescent. 12. A. mollissimus. 
Stems elongated; pods deeply grooved on the lower suture. 
Pods finely pubescent. 13. A. adsurgens. 
Pods villous with long spreading hairs. 14. A. goniatus. 
Pods fleshy, indehiscent; plants decumbent. 
Pods glabrous. 
Flowers violet-purple. 15. A. crassicarpus. 
Flowers yellowish-white. 16. A. mexicanus. 
Pods pubescent; flowers yellowish-white. 17. A. plattensis. 
