222 
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 oblique 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 asto 
show the close and reticulated corrugations, broadly sulcate ventrally 
below and decidedly obcompressed to near the tip, flattened but al- 
most never sulcate 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 
mostly 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 reflexed 
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 
mim. 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. inflexus, that is, the erect 
part as iong as base and abruptly rounded at least to erect, about 5 
mm. long from the lower end to the bend, 2mm. wide in the middle 
and ] mm. wide at the rounded tip. 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, with appressed !eaílets 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 closeand 
rather small mats, the crowns much branched and with rather woody 
roots which are erect, shallow and slender. This species abounds 
thie ‘ghout the Columbia Basin and nearly to the heads of all its 
streams 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 
Helena Mont., and into the Great Basin in northwestern Nevada, but 
never in the low humidity regions of the Great Basin. This applies to 
type only as to distribution. 
Astragalus Purshii var. interior N. Var. Thesis the white-flow- 
ered form of the Great Basin with the densely matted stems forming 
thick crowns which do not elongate. Leaves rarely 5 cm. long. The 
leaflets 6-8 pairs, elliptical, acutish, 5-8 nm. long, more hoary than the 
type. Flowers 1.5-2 cm. long and with narrow, not noticeably 
inflated calyx. Calyx teeth a third toa quarter as long as the tube. 
Braets and pedicels shorter. Banner hardly longer than the wings. 
Pods rarely over 1.5 cm. long, barely more than oblique, and with very 
‚short and ee s er tip mostly concealed in the dense woo! which : 
auoeraty concen s the shape of the pods. Wings horizontal at tip. 
_ This is the common form of the low humidity regions of the Great. 
eau in the mountains and foothills in gravelly or rocky soil from 
