Onopordum 



Compositae 



1003 



50 



Map 2200 



Cirsium discolor (Muhl.) Spreng. 



50 



Map 2201 



Cirsium altissimum (L.) Spreng. 



9467. ONOPORDUM [Vaill] L. 



1. Onopordum Acanthium L. Cottonthistle. Map 2202. In 1910 

 I found this species to be a common plant along the roadside about a 

 quarter of a mile north of Rosedale, Parke County. I passed along this 

 road in 1918, and it was still plentiful. In 1929 I found a large colony on 

 the bluff of the Ohio River near the roadside on the south side of Glendale 

 Cemetery, Dearborn County. There is a specimen from Jefferson County 

 collected by Stanley Coulter in the herbarium of Wabash College. It has 

 been reported also from Clark and Marion Counties. 



Nat. of Eurasia; N. B. and N. S. to Ont. and Mich., southw. to N. J. 



9476. CENTAUREA L. 



Some of the species of this genus have long been cultivated in gardens, 

 and seeds from them have found their way to roadsides and dumps. Speci- 

 mens from these have been collected and reported, but unfortunately, 

 little or no information accompanies the reports. No data are given as to 

 how long the species has been found in the same place or as to the size of 

 the colony. An annual species has been reported twice as found in alfalfa 

 fields. Since alfalfa is usually mowed from two to three times a year, 

 an annual would have little chance to perpetuate itself. It seems best to 

 regard all of our reports as garden escapes or chance introductions. I 

 prefer to be too conservative rather than to be too hasty in accepting exotic 

 species as a part of our flora. 

 Bracts of the involucre (at least the lower ones) tipped with stout prickles; flowers 



yellow; annual. (See excluded species no. 695, p. 1104) C. solstitialis. 



Bracts of the involucre lacerate or fimbriate, not prickly. 



Leaves pinnatifid into linear segments; bracts ribbed, pectinate at the black tip 

 only; annual or biennial. (See excluded species no. 693, p. 1104) . . . . C. maculosa. 

 Leaves entire, denticulate or some of the lower ones lobed. 



Tips of the involucral bracts not dilated; leaves linear or linear-lanceolate, entire 



or remotely denticulate; annual. (See excluded species no. 691, p. 1104) 



C. Cyanus. 



