69 
Genus 20. Strysum. 
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. (3) #.B.1.976. E. B.2,.1114. @. § Arn, 231. 
Bab.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. JulyandAug. Purple. (3) £&. B.1. 107. 
#. B.2.1115, H.§ Arn. 231. Bab. 188. Lind. 152. 
C. patustris. Marsh Thistle. Fig. 683. 
Leaves decurrent, pinnatifid, toothed, spinous. Involucrum ovate, 
scales nearly smooth. Flowers in close clusters. Marshes. 3-6 ft. 
Bienn. July and Aug. Purple or white. (4) FE. B.1.974, E. B. 
2.1116. H. § Arn.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. (4) 2. B. 1.975. E. B. 
2.1117. H. & Arn. 231. Bab. 189. Lind. 153. 
C. er1opHoRvs. 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. Julyand Aug. Purple orwhite. (4) 2. B.1.386. E. B. 
2.1118. H.& Arn. 232. Bab. 189. Lind. 153. 
C. ruserosus. 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. (3) #&. B. 1. 2562. EF. B. 2.1119. H. & Arn. 232. 
Bab.190. Lind. 153. 
C. HETEROPHYLLUS. Dark Plume Thistle. Fig. 687. 
Stems downy, mostly I-flowered. Leaves lanceolate, not prickly. 
Northern pastures. 2-3 ft. Perenn. July and Aug. Dark purple. 
(3) #&. B. 1. 675. FE. B. 2.1120. H. & Arn. 232. Bab. 190. 
Lind, 153. 
C. PpRATENSIS. 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. (4) £. B. 1. 177. 
KE. B. 2.1121. HH. & Arn. 232. Bab. 189. Lind. 153. 
C. acautis. Dwarf Plume Thistle. Fig. 689. 
Stemless. Involucrum smooth, sessile. Chalk pastures; abundant. - 
2in. Perenn. July. Purple. (4) #. B.1.161. #. B. 2, 1122. 
H. & Arn. 233. Bab.190. Lind. 153. 
Genus 22. OnoporpuM, 
O. Acantuium. Cotton Thistle. Fig. 690. 
Stem winged. Leaves sinuated, spinous, white and cottony. Scales 
of involucrum spreading. Waste places. 4-6 ft. Bienn. Aug. 
Purple. (3) #.B.1.977. FE. B, 2.1123, H.& Arn. 233. Bab. 187. 
Lind. 152. 
