356 COMPOSITZ HYMENOPAPPUS 
) RIGIOPAPPUS 
Achenes narrow, quadrangular. Pappus of several scarious scales 
with callous-thickened opaque base, rarely wanting. | 
B. oppositifolia Nutt. T. & G. Fl ii, 376. Herbaceous perennial;stems 
densely cinereous, much branched, 4-12 inches high, very leafy: leaves 
opposite, or the uppermost alternate, 6-18 lines long, palmately 2-5-parted 
into linear obtuse or obtusish, entire segments, finely cinereous on both 
sides: heads short-peduncled: involucre campanulate, or becoming hemi- 
spheric, its bracts oblong, obtuse, densely tomentose: rays 5-7, short: 
achenes linear-oblong, glandular-pubescent: pappus of 4-8 spatulate to 
lanceolate paleze with thickened bases. Dry plains, eastern Oregon to 
Nebraska and New Mexico. 
B. nudicaulis Gray Proc. Am. Acad. xix, 27. ‘‘ Cinereous-puberulent 
and glabrate, upper part of the scapiform stem and inyvolucre minutely 
glandular, a span or two high: leaves nearly all radical, oval or spatulate- 
oblong, (an inch or more long), tapering into a slender petiole : heads soli- 
tary, or few and somewhat corymbosely paniculate, nearly half-inch high: 
involucre hemispherical, of about 10 oblong bracts: rays 6-9, oblong: pap- 
pus fully half the length of the cuneate-linear sparsely hairy achene; the 
thin margins of the pales of the pappus erose and the short-excurrent awn 
barbellate-hispiduluus. Wind River Mountains N. W. Wyoming.,, To 
be looked for in Idaho. 
63 HYMENOPAPPUS L’Her. Michx. FI. ii, 103. 
Perennial or biennial herbs with sulcate-angled erect stems, 
alternate mostly once or twice pinnatifid or parted leaves, and 
ccorymbosely cymose or solitary pedunculate heads of yellow or 
white flowers. Involucre campanulate, many-flowered, of 6-12 
mostly appressed bracts with scarious-membranaceous usually 
colored tips. Rays none. Disk-corollas numerous, all alike, 
with narrow tube, abruptly dilated throat and reflexed or widely 
spreading lobes. Style-branches with short and thick conical 
appendages Achenes obpyramidal, 4—5-angled, with attenuate 
base, the faces 1-3-nerved. Pappus of 10-20 thin-scarious and 
mostly hyaline obtuse scales; sometimes very short or obsolete. 
__H. filifolius Hook. Fl. i, 317. Perennial from a deep woody root: stems 
usually tufted, 10-24 inches high, woolly when young, ensely leafy toward 
the base, usually naked and sparingly branched above; leaves rather rigid 
once or twice or the radical thrice pinnatifid into very narrowly linear or 
filiform divisions their margins soon revolute: heads few or solitary, 4-6 
lines high; bracts of the involucre oblong, usually densely woolly, with 
whitish or purplish tips: corollas white to way ind its reflexed lobes very 
much shorter than the throat: achenes densely villous: paleze of the pappus 
short. Brit. Columbia to California New Mexico and Nebraska, east of 
the Cascade Mountains. ; 
64 RIGIOPAPPUS Gray Proc. Am. Acad. vi, 548. — 
Small slender annual with opposite leaves and small heads of 
yellow flowers terminating the branches. Heads inconspicuously 
radiate. Involucre turbinate-campanulate, of numerous narrowly 
linear rather rigid herbaceous bracts which are somewhat inyo- 
lute at maturity ; many-flowered, Receptacle flat. Ray-flowers 
5-15, the corolla with slender tube.and oblong entire or 2-tooth- 
