HITCHCOCK — PLAXTS OF AMES, IOWA. 479 



tris and E. acicnlaris. though these combinations first formally 

 appeared in Roemer and Schultes' Systema Vegetabilium. 



Following the accepted names in the list, is the synonymy : 

 first, the original combination ; second, the combination used in 

 the last edition of Gray's Manual ; third, any others having a 

 critical bearing on the nomenclature. Following this, is the 

 habitat and frequency of occurrence. The latter is indicated by 

 the following terms, in the order given : common, abundant, fre- 

 quent, not uncommon, infrequent, scarce, rare. When the spe- 

 cies is rare, or known only for a few stations, these are indicated. 

 Names of indigenous and well established introduced species are 

 in small capitals ; those of species which do not appear to be 

 established, and hence are not real!}' a part of the fiora, are placed 

 in lower-case type ; but those which were formerly abundant, 

 and have become scarce, are retained in small capitals. No dis- 

 tinction has been made in the list between well marked varieties 

 and forms which have received varietal names. As the species 

 have been arranged under the genus on an equal footing, the 

 s.ime has been done with the varieties. 



Notes have been frequently introduced in order to call atten- 

 tion to ditKcult points, and that errors may be the more easilv 

 located. An attempt has also been made to discriminate between 

 closely allied species. 



In conclusion, I wish to thank those botanists whom I have 

 mentioned above, and also Dr. Trelease, who has given me valu- 

 able advice throughout the work ; Prof. L. H, Pammel. to whom 

 the inception of the work was due, for notes and specimens; JNIr. 

 Sirrene, for specimens collected during 1890, — and last, but 

 by no means least, Mr. H.J. Webber, who has kindlv consented 

 to undertake, in m}' absence, the arduous task of proof-readino-. 



SCOPE OF THE FLORA. 



The region included in this catalogue is essentially the vicinity 

 of the Agricultural College at Ames. Qiiite thorough explora- 

 tions have been made within a radius of three or four miles about 

 this point. From four to nine miles they have been confined to 

 certain directions ; viz., along the railroad from Ames to Gilbert, 



