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habitat, season of flowering, frequency of occurrence, and variations of life and 
growth, and also to speak of the localities of the rarer forms and of the disap- 
pearance of species, and to give such other notes as are of scientific interest. For 
the purpose of aiding collectors, localities are mentioned, in many cases, for 
species that are not especially rare. 
The exclamation point following an authority for location of species, is em- 
ployed to show that the writers have also found the plant in the locality indi- 
cated. In order to designate plants not heretofore listed by Babcock and Pat- 
terson, the initials B. and P. have been appended . Introduced forms are placed in 
small capitals. It is probable that some of the rarer forms have been introduced, 
but owing to the absence of any complete catalogue indicating the previous con- 
dition of our flora, we have listed them as native, when found growing apparently 
in a natural state. 
The area included in the Flora, is Cook County, Illinois, and that portion of 
Lake County, Indiana, situated north of the Little Calumet river. All plants 
recorded, with the exception of a few mentioned by Babcock, which are admitted 
on his authority, have been examined either by ourselves, or by Prof. E. J. Hill, 
and are contained in herbaria in Chicago and vicinity. 
The causes of extermination within our limits are varied. The phenomenal 
growth of Chicago and the establishment of manufactories in the suburbs, as well 
as the cutting of the forest growths, have largely tended to change the complexion 
of our native flora. 
As the catalogue is intended to be used in connection with the 6th edition of 
Gray’s Manual, it has been considered best to follow its general arrangement. 
While we cannot entirely endorse the nomenclature used in the 6th edition, we 
have adopted it with the following exceptions: 
Hepatica triloba, Chaix., is Anemone hepatica, L. 
Hepatica acutiloba, DC., is Anemone acutiloba, Lawson. 
Nymphsea, is Castalia, Salisb. 
Nuphar, is Nymphasa, L. 
Lechea minor, L., var. maritima, Gray, is L. maritima, Leggett. 
Viola palmata, L., var. cucullata, Gray, is V. cucullata, Ait. 
Carya, is Hicoria, Baf. 
Quercus coccinea, Wang., var. tinctoria, Gray, is Q. tinctoria, Bartram. 
The ConiferaB have been placed in their more natural position, at the end of 
the Monocotyledons. 
In all cases the nomenclature of the 5th Ed. of Gray’s Manual has been 
shown, when differing from the 6th. 
It is fitting that this catalogue, following the list of Prof. Babcock, which was 
the first and only botanical record of this section, should contain a tribute to his 
personal worth and his valuable contributions to the science of botany, and it is 
well that this recognition of his ability should come from his friend, Prof. E. S. 
Bastin, to whom we are also indebted for many notes and suggestions. 
The authors desire to acknowledge the generous assistance of Dr. Oliver 
Marcy, who during the many years in which he has been an honored professor in 
Northwestern University, has become thoroughly acquainted with the geology 
and the natural history of this region. 
The editing of the Genera Lechea and Potamogeton, and the revision of the 
genus Carex, are by Prof. E. J. Hill, who has also contributed valuable notes. 
