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Genus 20. Silybum. 
S. Marianum. Milk Thistle. Fig 681. 
Leaves waved, spinous, glossy green with white veins. Spines of 
involucrum very large, recurved. Waste places. 4-5 ft. Bienn. 
July. Purple. (|) E.B.1.97G. E.B. 2.1114. H. ^ Am. 231. 
Bub. 190. Lind. 154. 
Genus 21. Cnicus. 
C. lanceolatus. Spear Thistle. Fig. 682. 
Stem hairy, furrowed. Leaves spinous, cottony beneath. Involucrum 
ovate, with lanceolate spreading scales. Flowers solitary. Waste places ; 
common. 3-4 ft. Bienn. July and Aug. Purple. Q) E. B. 1. 107. 
E. B.2. 1115. H.fyArn. 231. Bab. 188. Lind. 152. 
C. palustris. Marsh Thistle. Fig. 683. 
Leaves decurrent, pinnatifid, toothed, spinous. Involucrum ovate, 
scales nearly smooth. Flowers in close clusters. Marshes. 3-6 ft. 
Bienn. Juiy and Aug. Purple or white. (|) E. B. 1.974. E. B. 
2.1116. H. fy Am. 231. Bab. 189. Lind. 152. 
C. arvensis. Common Thistle. Fig. 684. 
Root creeping. Stem panicled, solid. Leaves sessile, pinnatifid, 
spinous, deep shining green, nearly smooth. A common weed. 1-3 ft. 
Perenn. July. Pale purple or whitish. (|) E. B. 1. 975. E. B. 
2. 1117. H. Am. 231. Bab. 189. Lind. 153. 
C. eriophorus. Woolly-headed Thistle. Fig. 685. 
Stem very thick, furrowed. Leaves deeply pinnatifid, downy beneath. 
Involucrum spherical, woolly. Limestone pastures and waste places 
3-4 ft. July and Aug. Purple or white, (g) E. B. 1. 386. E. B 
2.1118. H. fy Am. 232. Bab. 189. Lind. 153. 
C. tuberosus. Tuberous Plume Thistle. Fig. 686. 
Root creeping, tuberous. Stem 1- or 2-flowered, not prickly. Leaves 
pinnatifid, with small prickles. Woods. 2 ft. Perenn. Aug. Bright 
purple. (|) E. B. 1. 2562. E. B. 2. 1119. H. fy Am. 232. 
Bab. 190. Lind. 153. 
C. heterophyllus. Dark Plume Thistle. Fig. 687. 
Stems downy, mostly 1-flowered. Leaves lanceolate, not prickly. 
Northern pastures. 2-3 ft. Perenn. July and Aug. Dark purple. 
(|) E. B. 1. 675. E. B. 2. 1120. H. Am. 232. Bab. 190. 
Lind. 153. 
C. pratensis. Meadow Plume Thistle. Fig. 688. 
Stems downy, 1-flowered. Leaves lanceolate, green above, cottony 
beneath, with small spines. Involucrum cottony. Wet meadows and 
heaths. 1 ft. Perenn. July. Dull purple. (|) E. B. 1. 177. 
E. B. 2. 1121. H. Am. 232. Bab. 189. Lind. 153. 
C. acaulis. Dwarf Plume Thistle. Fig. 689. 
Stemless. Involucrum smooth, sessile. Chalk pastures; abundant. 
2 in. Perenn. July. Purple. (|) E. B. 1. 161. E. B. 2. 1122. 
II. & Am. 233. Bab. 190. Lind. 153. 
Genus 22. Onopordum. 
O. Acanthium. Cotton Thistle. Fig. 690. 
Stem winged. Leaves sinuated, spinous, white and cottony. Scales 
of involucrum spreading. Waste places. 4-6 ft. Bienn. Aug. 
Purple. (4) E.B. 1.977. E.B. 2.1123. H.fyAm.233. Bab. 187- 
Lind. 152. 
