PRELIMINARY REVISION OF THE GENUS INGA. 
By Hewry PITTIER. 
INTRODUCTION. 
In the course of his work on the flora of Panama, the author has 
found it almost impossible to proceed in the determination of the 
species of Inga without attempting a revision of the whole genus. 
Since the publication of Bentham’s extensive monograph, in 1875, 
no general study of this important group has been undertaken, al- 
though many new species have been described by Micheli, Harms, 
Oliver, Britton, and others. It is now found that the arrangement 
of the species has to undergo certain slight changes, that there have 
been misconceptions and unjustifiable modifications in the status of 
many species, and that a considerable number of new types await 
description in the American collections at hand. Of the latter, 
several collected by the author and others in Panama, Central 
America, and Venezuela are of unusual interest. 
It was thought possible at first to limit the present study to a re- 
vision of the Inga species in the United States National Herbarium, 
but while this collection is relatively rich in new material, it did not 
offer many opportunities for comparison and definition of old types. 
This led to the present extension of the investigation, which em- 
braces the material contained in most of the larger American 
herbaria. 
The curators of the Gray Herbarium, the New York Botanical 
Garden, and the Field Museum of Natural History have most oblig- 
ingly lent their extensive collections, for which grateful acknowledg- 
ment is here made. The Gray Herbarium is especially rich in speci- 
mens from old collectors, some of which are duplicates of types ( if 
not the types themselves) of Schlechtendal’s Mexican species, and 
many others the types or duplicates of types of Bentham’s South 
American species. The John Donnell Smith Herbarium, always 
generously put at the disposal of botanical students, has also been 
freely consulted. Besides, the Director of the National Museum of 
Costa Rica had the kindness to lend the rich local collection of the 
defunct Instituto ffsico-geografico, made mainly under the direction 
of the writer. 
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