196 NORTH AMERICAN FLORA 
Pappus (at least in the ray-flowers) of bristles or awns, only occasionally 
paleaceous at the base, rarely with an additional outer set of minute 
squamellae, or rarely reduced to a mere crown. 
Pappus of slender, filiform bristles, or rarely dilated below, erect, or a 
mere crown. 
Pappus-bristles usually 10 or more, at least in the disk-flowers. 
Perennials with a more or less woody caudex or rootstock; 
heads on long peduncles. 
Heads solitary. 
Involucre 6-8 mm. high; leaves 1.5—10 mm. wide. 
Leaves ascending, the tips arcuate-spreading, long- 
attenuate; bracts 5, acute. 
Leaves spreading, neither arcuate nor attenuate. 
Involucral bracts 12-15, narrowly linear. 
Involucral bracts 5—12, oblong to obovate. 
Leaves linear-lanceolate. 
Bracts 5-7, rounded at the apex. 
Involucral bracts 5, obovate or oval. 
Pappus of the ray-flowers of several 
bristles; bracts obovate, over- 
lapping, ciliate. 
Pappus of the ray-flowers of two 
stout awns dilated at the base 
and about 20 slender bristles; 
bracts oval, pubescent at the apex. 
Involucral bracts 5-7, oblong or elliptic, 
not overlapping, usually puberulent; 
pappus of the ray-flowers of short 
squamellae. 
Bracts 7-12, acutish. 
Involucral bracts puberulent, rather 
firm; pappus of the ray-flowers wanting. 
Involucral bracts glabrous, thin; pappus 
of the ray-flowers of a few bristles. 
Leaves broadly oblanceolate. 
Involucre 5 mm. high; leaves less than 1 mm. wide. 
Heads in leafy cymes; involucre 5 mm. high or less. 
Bracts 8; bristles of the ray-flowers 2. 
Bracts 5; bristles of the ray-flowers several. 
Annuals. 
Peduncles longer than the leaves. 
Leaves stiff, spinulose-tipped, crowded; ray-flowers with 
many pappus-bristles. 
Stems 2-3.5 cm. high; leaves bristly-ciliate to near 
the apex, with 5-7 pairs of bristles; involucre 
6-6.5 mm. high. 
Stems about 1 dm. high; leaves bristly-ciliate only 
below the middle, with 3-5 pairs of bristles; involucre 
5—6 mm. high. 
Leaves soft, merely mucronate, scattered; ray-flowers 
with 2—6 pappus-bristles. 
Bracts 8-12. 
Stem puberulent; involucral bracts 4 mm. long. 
Stem glabrous or nearly so; involucral bracts 5-6 
mm. Jong. 
Leaves linear; stem leafy. 
Bracts acute. 
Bracts obtuse. 
Leaves oblanceolate; stem leafy only at the base; 
bracts obtuse. 
Bracts about 5, 4-5 mm. long. 
Involucral bracts rounded at the apex. 
Involucral bracts acuminate. 
Peduncles shorter than the leaves. 
Plants tall, erect; bracts thin, keeled only at the base; ligules 
purple-tinged, erect; disk-corollas with short lobes. 
Plants low and diffuse; bracts thick, round-keeled to the 
apex, strongly involute on the margins; ligules light- 
yellow, spreading; disk-corollas with long lobes. 
Pappus-bristles few, 1-6, or represented by a mere crown. 
Involucral bracts about 8. 
Bracts narrow, strongly carinate and involute; corolla-tube 
as long as or longer than the throat and limb together; 
heads usually subsessile or short-peduncled. 
Pappus of a shallow cup or crown, with or without 1 or 2 
bristles. 
Leaves not dilated, merely ciliate at the base. 
Leaves dilated and lobed at the base. 
Pappus merely 2-6 bristles. 
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[VOLUME 
. diffusa. 
. longipes. 
latisquama. 
repens. 
canescens. 
salurejoides. 
polyantha. 
Liebmannii. 
Leonis. 
stenophylla. 
capillipes. 
pusilla. 
. P. juniperina. 
puberula. 
Palmeri. 
Mearnsit. 
Barberi. 
Haenkeana. 
Schottit. 
elongata. 
papposa. 
papposa. 
angustifolia. 
34 
