410 



are placed together iiuder this one general "catch all" name, which has no 

 particular significance. Field observations and cultures, along with further 

 microscopical work, are necessary to segregate these forms. No doubt some 

 of them will be found to belong with aecial forms already connected, 

 while others of these forms will doubtless be found to have new heteroe- 

 cious connections.) 

 On CARDUACEAE: 



ColeosantJiits grandiflorus (Hook.) Kuntze {BrickclUa grandiflora 

 Hook.), New Mexico. 



Chnjsogouum virginianum dcntatuiii A. Gray. District of Columbia. 



Chrysotlianiiius Parnji (A. Gray) Greene {Aitl<q)(ii>pii>< I'amji A. Gray) 

 New ^lexico. 



Dugaldia Iloopsii (A. Gray) liydb. {IlcJciihon Iloopsil A. Gray), Col- 

 orado. 



UclenUim autumnalc L., Colorado. 



Polymnia canadensis L., Iowa, Wisconsin. 



RudVcckia hirta L., Nebraska. 



Rudhcckia laciniata L., Iowa, Nebraska, Wisconsin, Wyoming. 



Rudbcckia triloba L., Delaware. 



ACKXUWLKl )( J.MHXTS. 



The writer wishes here to express his sincerest tlianks to all who have 

 assisted in any way in the pursuance of this study. The kindly attention 

 and critical suggestions of Dr. J. C. Arthur, under whose dii'ectiou the 

 wtjrk has been done, has been greatly appreciated throughout. Acknowl- 

 edgments are espwially due Dr. Arthur for the ft*ee u.se of his exception- 

 ally large private collection of plant rusts, as well as for free access to 

 his extensive private library on this subject, without eitlicr of wliich this 

 study would not have been i)ossible at tills time. Free use was also made 

 of his private card indices and manuscrii>t sheets on the subject, which 

 very greatly facilitated the use of both the library and the herbarium, and 

 where much information was already brought together in available form. 



Sincere thanks are al.'^o extended to the other members of the botan- 

 ical department ftf the Indiana Experiment Station, viz: to Dr. Frank D. 

 Kern, Mr. C. K. Orton. Miss Evelyn Allison and Miss Mary A. Fitch, for 

 kindly assistance in various ways. 



