COMPOSITE FAMILY 249 



large, surrounded by a wliorl of linear-oblong, comb-like leaves ; in- 

 volucral bracts linear, ciliate, not spine-tipped. Flowers purple or 

 yellowish. On sandy soil E. and S.* 



2. C. virginianum Miclix. Early AVood Thistle. 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. Bachelor'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 i-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 Thistle. 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 aj> 

 pendages. Flowers pink or purple, the marginal ones ray-like. In dry 

 plains, especially S.W. 



n. LIGULIFLORiE 

 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 



