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ROBINSON. — ALSINEA. 273 
XIV. 
CONTRIBUTIONS FROM THE GRAY HERBARIUM OF HARVARD 
UNIVERSITY, NEW SERIES, NO. VI. 
By B. L. Rosinson. 
Presented January 10, 1894. 
I.— THE NORTH AMERICAN ALSINE. 
Tue following provisional treatment of the North American 
Alsine@ is based principally upon the material in the Gray Herbarium. 
An effort, however, has been made to see as large a representation of 
the group as possible, and with this end in view a number of other 
large and valuable collections have been visited ; namely, the herbaria 
of the Department of Agriculture, Columbia College, the Missouri 
Botanical Garden, the Philadelphia Academy of Natural Sciences, the 
Boston Natural History Society, and the private collections of 
Mr. William M. Canby of Wilmington, Del., Mr. John Donnell 
Smith of Baltimore, and Mr. Walter Deane and Mr. Edward L. Rand of 
Cambridge, Mass. Those in charge of all these collections have most 
kindly allowed their Caryophyllacee to be examined, and all such 
specimens as showed any noteworthy peculiarities to be brought to 
Cambridge for critical study. From the herbaria of the Canadian 
Geological Survey, Iowa Agricultural College, and Natural History 
Society of Wilmington, Del., the entire representation of Alsinee 
has also been most obligingly forwarded to the Gray Herbarium for 
examination. 
While the study of such copious materials has obvious advan- 
tages, it by no means lessens, but rather increases, the difficulties of 
classification. In a long series of specimens individual variation 
becomes apparent in a way which can scarcely be realized if study is 
confined to fewer plants. Specific limitations often become very 
obscure, and sharp definition almost or quite impossible. Several 
instances of such practically confluent species occur in the present 
group, and in adjusting specific lines there is consequently great room 
for difference of opinion. Free criticism and friendly aid will be very ee 
VOL. XXIx. (N. 8. XX1I.) eo 
