astragalus. LEGUMINOS M. 143 



11 ASTRAGALUS Tourn. (Rattle weed, Loco-weed). 



Erect or decumbent herbs with unequally pinnate leaves with- 

 out tendrils, persistent stipules and axillary spikes or racemes of 

 rather small, narrow flowers. Calyx 5-toothed. Petals with 

 slender claws, the keel obtuse. Stamens diadelphous. Stigma 

 terminal, minute. Pod very various, commonly turgid or in- 

 flated, one or botli sutures often projecting inward more or less, 

 the dorsal one frequently so much as to divide the cell into two, 

 rarely Hat. Seeds few or many, on slender stalks, generally 

 small for the size of the pod. 



Series I. Astragalus L. gen. n. 892 as genus. Pod com- 

 pletely or imperfectly 2-celled by the intrusion of the dorsal su- 

 ture, the ventral suture being not at all or less deeply intruded. 



§ 1 Diphysi Gray Proc. Am. Acad, vi, 193. Pods ovate or 

 globose, membranaceous or coriaceous, inflated, glabrous or 

 nearly so, sessile, completely 2-celled and more or less did vinous 

 by the intrusion of both sutures, several -seeded : pubescence 

 short or wanting: flowers rather small, white to purple or yel- 

 lowish, spicate or subspicate. 



A. araneosns Sheld. Bull. Minn. Nat. Hist. Surv. No. 9, 170. Gla- 

 brous throughout or slightly pubescent when young : stems decumbent or 

 assurgent, (5-18 inches long, very finely striate, simple, few to many from 

 a thick perennial root: leaves 4-6 inches long, the rachis slightly winged, 

 not channeled or hut slightly so: stipules deltoid-acuminate, semi-sheath- 

 ing below, reflexed; leaflets 6-8 pairs, 5-6 lines long, somewhat fleshy, or- 

 bicular or obcordate, obtuse, retuse or emarginate; peduncles equalling 

 the leaves, striate, capitately or subspicately 10-12 flowered; calyx short- 

 cylindrical, with a few scattered, blackish hairs, the linear spreading teeth 

 K->e the length of the tube; petals whitish tipped with purple: pods 

 ovate-lanceolate, arcuate-incurved, with a long acuminate incurved beak, 

 6-10 lines long, coriaceous, glabrous, minutely reticulated, sessile, both 

 sutures intruded so as to form a nearly 2-celled cavity which is lined 

 throughout with fine cobwebby hairs, 8-10-seeded. On dry plains and 

 hillsides, Eastern Oregon and Washington to Utah. 



A. lentiginosus Dougl. Don Syst. Gard. and Bot. ii, 257. Slightly pu- 

 bescent: stems tufted, 6-12 inches long, soon diffusely spreading: stipules 

 small, ovate, acute; leaflets 11-19, from obovate or oblanceolate to oblong, 

 3-b lines long: pods turgid, ovate, acuminate, more or less incurved, 4-6 

 lines long, puberulent, often mottled, thick-membranaceous sessile, 2-cel- 

 led by the intrusion of both sutures, 6-8-seeded. Dry plains, Brit. Colum- 

 bia to California and Nevada. 



A. saliiius Howell Eryth. i. 111. Minutely hirsute: stems numerous 

 from a thick perennial root, decumbent or ascending, rather slender 4-s 

 inches long, much branched: leaflets 9-17, obovate to oblong, obtuse or 

 retuse. 4-6 lines long: peduncles shorter than the leaves: calyx narrow. 

 its short subulate teeth half as long as the tube; Mowers yellowish. 6-8 

 lines long: pods inflated ovoid, short-beaked, chartaceous, 6-8 lines long, 

 very glabrous, nearly 2-celled by the intrusion of the dorsal suture, sev- 

 eral-seeded. In saline soil, Harney valley, southeastern Oregon. 



A. diaphanus Dougl. Hook. Fl. i. 151. Prostrate and diffuse, pilose- 

 scabrous; stipules small, ovate, acuminate; leaflets' 1 1-19. obovate : pedun- 

 cles shorter than the leaves ; flowers about <> lines long, purple, in loose 

 heads; bracts minute, ovate, acuminate rather shorter than the pedicels: 



