240 GLEASON: TAXONOMIC STUDIES IN VERNONIA 
VERNONIA RIGIDA Sw. 
Collected originally by Swartz in Jamaica in the middle of the 
eighteenth century, this excellent species has since been practically 
lost. Few botanists have examined Swartz’s originals and as a 
result the name V. rigida has been applied by various collectors 
and students to several entirely different species. The genuine 
V. rigida was finally rediscovered by Wm. Harris at Upper Claren- 
don, Jamaica, December 27, 1917, and good specimens are now 
deposited in the herbaria of the Field Columbian Museum and the 
New York Botanical Garden. The species is obviously allied with 
the well-known Jamaican V. acuminata Less. 
Vernonia Sagraeana angusticeps (Ekman) var. nov. 
Vernonia angusticeps Ekman, Ark. Bot. 13:14. 1914. 
The sheet of Wright 284, on which the species of Ekman was 
based, in the Gray Herbarium agrees with the species in every 
particular except the small number (twelve) of flowers in the head 
and the consequently more nearly cylindrical involucre. 
SPECIES-GROUP BUXIFOLIAE 
In the mountains of Haiti and Santo Domingo occurs a group 
of three poorly known species of Vernonia. Only eight speci- 
mens have been examined in American herbaria by the writer, 
while Ekman mentions twelve in various European collections. 
One of these, the last to be described, is V. Tuerckheimii Urban, 
which seems to a well-marked and easily recognized species. 
Another is a form with small leaves, averaging only 7 X 12 mm. 
and a short, cylindrical or ellipsoid involucre 3-4 mm. in diameter, 
or spreading under pressure to 5 mm. For convenience this will 
be designated here as species A. The third, here referred to as 
species B, has leaves averaging 10 X 23 mm., and a turbinate oF 
almost salviform involucre, spreading at its mouth to a width a 
7-9 mm. even when not pressed. While the involucre of species 
A offers no noteworthy feature, that of species B is remarkable for 
its imbrication. It is composed of five vertical but gently spiral 
rows of scales, with ten to thirteen scales in each row, beautifully 
imbricated, and with the outer ones gradually reduced at the 
acuminate base of the head. Ekman had before him apparently 
