COMPOSITE FAMILY 249 
large, surrounded by a whorl of linear-oblong, comb-like leaves; in- 
volucral bracts linear, ciliate, not spine-tipped. Flowers purple or 
yellowish. On sandy soil E. and S8.* 
2. C. virginianum Michx. Earty Woop TuistLe. Stem woolly, 
slender, little or not at all branched, 1-3 ft. high. Leaves lanceolate, 
green above, covered beneath with dense white wool, the margins 
beset with prickly bristles, entire or sinuate-lobed, the lower ones 
sometimes pinnately cut into triangular-lanceolate lobes. Heads 
small, purple, on long leafless peduncles; outer scales of the involucre 
merely bristle-pointed. In dry woods and thickets. 
XIII. CENTAUREA L. 
Herbs. Leaves entire or cut, often spiny-toothed. Heads 
single; involucre ovoid or globose; bracts closely overlap- 
ping, often fringed, dry and membranaceous. Corollas all tubu- 
lar, oblique or 2-lipped, inflated above ; the outer ones usually 
larger and neutral, the inner flowers bisexual; lobes 5, slender. 
Akenes flattened; pappus hairs short, slender, rough. 
1. Cyanus L. Bacuetor’s Button. Stem erect, slender, grooved, 
1-2 ft. high, somewhat branched. Leaves acute, sessile, narrow, entire 
or few-lobed. Peduncles covered with cottony wool. Heads 3-1 in. 
in diameter, cobwebby. Ray-like flowers few, large, bright blue or 
pink; those of the disk smaller. Cultivated from Europe and escaped 
from gardens. 
2. C. americana Nutt. Prairie Star TuHisTLe. Annual; stem 
stout, little or not at all branched, 2-6 ft. high. Leaves entire or 
minutely toothed, the basal and lower ones spatulate or oblong, 
petioled, the upper narrower, sessile and mucronate. Heads solitary 
at the summit of the stem or tips of the branches; involucre nearly 
hemispherical, the bracts ovate or lanceolate, with comb-like ap- 
pendages. Flowers pink or purple, the marginal ones ray-like. In dry 
plains, especially S.W. 
II. LIGULIFLORZ 
XIV. CICHORIUM L. 
Perennial herbs with spreading branches; juice milky. 
Leaves radical and alternate, toothed or pinnately cut. Heads 
axillary; involucre cylindrical; bracts in 2 rows, the inner 
row erect, united at the base, the outer shorter; receptacle 
flattish. Corollas blue, pale pink, or yellow. Upper part of 
the style and its slender arms hairy. Akenes crowded on the 
