IOWA ACADEMY OF SCIENCES. 
233 
This species is common in Nebraska and Colorado, but 
in western Nebraska, Kansas and Colorado the species has 
a tendency to vary into the var. megacephalus. 
Distribution. — Kossuth County, Pammel, 607 I. S. C. 
Also reported from Muscatine County. 
REFERENCE TO OCCURRENCE IN IOWA. 
Barnes, Miller, and Reppert, FI. Scott and Muscatine 
Counties. 234. 
CNICUS UNDULATUS,VAR. MEGACEPHALUS, A. Gray. 
C. undulatus var. megacephalus. A. Gray. Proc. Am. 
Acad. 10 : 42. 1874. 
. Syn. FI. N. Am. 1 : 408. 1884. 
Carduus undulatus megacephalus. (A. Gray.) Porter 
Mem. Tor.' Bot. Club 5: 845. 1894. 
Britton & Brown, Illustr. FI. N. St. 3: 486. 
1898. 
Branches bearing single large heads with purple flowers two 
to two and one-half inches high, involucre more or less strongly 
appressed, scales with a prominent glutinous ridge, achenium four 
lines long, striate. 
Distribution , Iowa. — Boone, introduced, G. W. Garver. 
CNICUS CANESCENS, Pammel n. c. 
Cnicus undulatus var. canescens. Gray. Proc. Am. Acad. 
10:42. 1874. 
. Gray. Syn. FI. N. Am. 1 : 403. 1884. 
Cirsium canescens. Nutt. Trans. Am. Phil. Soc. 7: 420. 
. Torrey & Gray. FI. N. Am. 2 : 461. 1843. 
Branching perennial two to four feet high, woolly throughout, 
branches bearing single medium sized heads, stem angled, white 
woolly; leaves, radical eight inches to a foot long, the divisions 
usually two-lobed, prominently ribbed, ending in i* tout spines; stem 
leaves, except the lower, one to four inches long, pinnatifid, the 
upper sessile, slightly undulate with numerous sharp bristles, the 
upper surface slightly roughened, and a slight cottony down, the 
lower white woolly; heads one one-half to two inches high, bracts 
of the involucre somewhat arachnoid, lower scales with a broad 
base, glutinous ridge, and ending in a minutely serrated spine, 
inner scales long attenuated, tips straw-colored; flowers purple. 
