— 14 | 7 2 
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SMITHSONIAN INSTITUTION 
UNITED STATES NATIONAL MUSEUM 
CONTRIBUTIONS 
FROM THE 
UNITED STATES NATIONAL HERBARIUM 
VOLUME 20 
SYSTEMATIC STUDIES 
OF 
AMERICAN PLANTS 
BLAKE, EVANS, PAYSON, PENNELL, PIPER, 
PITTIER, STANDLEY, VAN ESELTINE 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1917-1925 
