Cerastium arvense, L., and its North American Varieties. 

 By Arthur Hollick and N. L. Britton. 



Plates LXIII-LXV. 



While botanizing on Staten Island, New York, during the 

 past ten or twelve years, our attention was frequently attracted 

 by a Cerastium, which grows abundantly at many places on the 

 serpentine hills, and in no other parts of the Island. This plant 

 agrees in general with the description of C. oblongifolhun, 

 Torrey, in the Flora of the State of New York, and yet it exhib- 

 its such a variety of forms that we were led to collect a large 

 number of specimens and memoranda for comparison. The 

 further the subject was investigated the more interesting it 

 became to us, and finally resulted in the study of not only this 

 plant, but of allied forms from other places. Our studies have 

 resulted in the conclusion that the Staten Island plants are more 

 properly to be regarded as a variety of C. arvense, L., and that 

 many other American forms of Cerastiwn are to be referred to 

 varieties of this species, as modified by climate, soil, etc. 



In addition to specimens in our own collections and those in 

 the herbarium of Columbia College, others from the following 

 herbaria have been kindly placed at our disposal : Harvard 

 University, United States Department of Agriculture, Academy 

 of Natural Sciences of Philadelphia, and Torrey Botanical Club. 

 In addition to these, we have received specimens and notes from 

 Prof T. C. Porter, Mr. C. E. Smith, Mr. W. M. Canby, Mr. J. M. 

 Macoun, Dr. J. C. Arthur, Prof S. M. Tracy, and others. 



The following is our proposed arrangement of the North 

 American forms of the species : 



Cerastium arvense, L. Leaves hnear or narrowly lanceo- 

 late ; those of the stem distant ; stem and leaves hairy or nearly 



