a23 



181 Astragalus Purshii Douglas in Hook. Fl. Bor. Am. 1 152 (1834) 

 This is a very variable species. The type pods oblong-oval to broadly 

 ovate and lunate, very obliciue or arched at least toward the tip, 1.5-2 

 cm. long, nearly 1 cm. wide, and 3-4 mm. high, with cross-section ren- 

 iform, sessile and rounded at base, densely short-woolly-shaggy with 

 short hairs rather closely felted and with other longer hairs which are 

 about straight and 2 mm. long, the pubescence mostly concealing the 

 surface but not the shape, or pubescence very rarely so short as to 

 show the close and rcliculated corrugations, broadly sulcatc ventrally 

 below and decidedly obcomprcssed to near the tip, flattened but al- 

 most never sulcatc dorsally, rarely arcuate to one third circle, with 

 both sutures thick and raised externally, with tip a little flattened 

 when dry and deltoid and hardly as long as wide but very sharp and 

 most!) erect, jointed to the calyx. Green pods very thick but grow- 

 ing thinner as they mature, completely filled by the large seeds and 

 cutting like wood. Flowers 2 cm. long, dull-white, with purple keel, 

 appearing a little yellowish when dry, the heads a little elongated and 

 with rachis 2-3 cm. long, but with its internodes shorter than the 

 bracts. Banner broadly elliptical, about 1 cm. long, with sides refiexcd 

 2-3 mm. wide in the middle at length, rather abruptly arcuate from 35- 

 45 degrees beyond the calyx, tips and then nearly straight to the end, 

 fleshy below, waterlined and inclined to fiddle-shaped. Groove 2 

 mm. wide and nearly as deep, narrowed and deeper below. Wings 

 linear to oblong, abruptly narrowed beyond the ears, about 1 mm. 

 wide, rounded, a little arched, 2-3 mm. longer than keel and nearly as 

 much shorter than banner. Keel as in A. inflcxus, that is, the erect 

 part as long as base and abruptly rounded at least to erect, about 5 

 mm. long from the lower end to the bend, 2 mm. wide in the middle 

 and 1 mm. wide at the rounded lip. Calyx tube about 1 cm. long and 

 3-5 mm. wide, inclined to be a little inflated, fleshy at base, triangular- 

 ly and somewhat obliquely inserted, with upper side a little arched, 

 softly and thinly woolly, with the teeth variable, but about half as 

 long as tube and triangular-subulate. Pedicels 3-4 mm. long. Bracts 

 linear-lanceolate or narrower, about 1 cm. long. Peduncles rather 

 slender but variable and shorter than the leaves. Leaves narrow, 5-8 

 cm. long, rather dull, wiih apprc-r-ed leaflets in 3-5 pairs, with petioles 

 nearly as long as the leaf-rachis. Leaflets rather narrowly elliptical, 

 acute at both ends and inclined to be folded, 5-15 mm. long, sparsely 

 long silky-woolly but pubescence rarely dense enough to conceal the 

 dark-green surface, somewhat strongly petiolulate and rather distant 

 Stems prostrate, slender but short and with the internodes rarely as 

 long as the acuminate and elongated stipules. Plants forming close and 

 rather smallmats, the crowns much branched and with rather woody 

 roots which are erect, shallow and slender. This species abounds 

 thio g'loul the Columbia IJasin and nearly to the heads of all its 

 st ca.ijs as far up as the middle of the Middle Temperate life zone, also 

 running over the eastern divide to the Laramie plains and probably to 

 Vlelcna Mont., and into tiie Great liasin in northwestern Nevada, l)ut 

 never in the low humidity regions ol the Great ILisin. This applies to 

 type only as to distribulion. • 



Astragalus Purshii var. interior N. Var. Thes is the white-flow- 

 ered form of the Great l'>asin with the densely matted stems forming 

 thick crOv.Mis which do not elongate, f^eaves rarely 5 cm. long. Tiie 

 leaflets 6-8 pairs, elliptical, acutish, 5-8 nm. long, more hoary than the 

 tyi)e. Flowers 1.5-2 cm. long and with narrow, not noticeably 

 inflated calyx. Cah'x teeth a third to a (|uarter as long as the tube. 

 Bracts and pedicels shorter. Banner liardly longer than the wings. 

 Pods rarely over 1.5 cm, long, barely more than oblique, and with very 

 shortand inconspicuous tip mosMy concealed in the dense wool which 

 generallj- conceals the nhape of tlie pods. Wings horizontal at tip. 

 This is the common form of the Inr.- humidity regions of the Great 

 P!ate.-iu in the mountains and foothills in gravelly or rocky soil from 



