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A Revision of the North American Vernonieae 
By HENRY ALLAN GLEASON j 
Several years ago it became apparent that certain species of 
Vernonia abundant in the western states had been so confused in 
various publications that satisfactory identification of them was 
almost impossible. Extensive field-work and detailed study of 
these doubtful species was alone insufficient to solve all the diffi- 
culties connected with them, so the investigation was extended first 
to include all the species of the United States and finally all the 
North American species of the tribe Vernonieae to which the 
genus Verzonza belongs. As far as possible the geographic-mor- 
phological method of Wettstein has been used, with results that it 
is hoped will prove of some value. The work has been done for 
the most part in the herbarium of the New York Botanical Garden, 
and it is a pleasure to acknowledge the valuable aid and criticism 
given by Professor N. L. Britton, Professor L. M. Underwood and 
Dr. P. A. Rydberg. Herbarium cares assistance and sug- 
gestion have also been given by . C. Adams, of the Uni- 
versity of Michigan, Mr. ad Brown, of the Academy of 
Natural Sciences of Philadelphia, Dr. B. L. Robinson and Mr. M. 
L. Fernald, of the Gray Herbarium, Mr. William R. Maxon, of the 
United States National Herbarium, and Director William Trelease, 
of the Missouri Botanical Garden. 
The Vernonieae as a group are characterized by homogamous 
discoid heads, anthers sagittate at base, styles subulate, leaves 
alternate and corollas not yellow. The shape of the style-branches 
is of particular importance, especially in distinguishing certain 
members of the group from alternate-leaved Eupatorieae. The 
branches are approximately semi-cylindrical in section and taper 
regularly from the point of division to the apex. The stigmatic 
surface is on the inner flattened side; the outer side is covered with 
hairs. The genera Rolandra and Spiracantha are anomalous in 
having the style-branches much shorter than is usual, but the hairi- 
ness of the outer surface extends much below the point of division, 
indicating a possible fusion of originally separate branches. The 
white, red, pink, or purple corollas are usually regularly five-cleft. 
In Elephantopus the corolla is more deeply cleft on the inner side. 
