207 
In some of the tribes the characters are more constant and 
uniform than in others. In.the tribes Vernoniacez, Eupatoriacee 
and Asteroidez, the characters of the style are very uniform and 
constant for each tribe, and therefore can be used with great ad- 
vantage. In the tribe Asteroidez, sufficient structural differences 
occur in the genera studied to make two divisions. 
In the tribes Helianthoideze and Cynaroidez, the characters 
are sufficiently uniform and constant to be of great aid, though 
not as much as in Vernoniacee, Eupatoriacee and Asteroidee. 
In the Helenioidez, Anthemidez and Senecionidee, there is 
less uniformity and constancy. The style structure is similar in 
all three tribes, and is of two general kinds. One is constant 
and distinct for the three tribes, but the other is not sufficiently 
distinct to prevent its being confused with Helianthoidee, but it 
would hardly be mistaken for~WVernoniacez, Asteroidex, or 
Eupatoriacez. In these tribes, therefore, the style characters 
cannot be used as distinctive marks for each tribe, but for the 
three tribes considered collectively. 
Another difficulty met with is in dicecious flowers of Inuloidez 
and Helianthoidee. In these tribes the characteristic arrange- 
ment of the brush hairs and stigmatic papilla cannot be used as 
characters, since the flowers are either sterile or fertile and pisti- 
late, and so do not possess both brush hairs and stigmatic papil- 
la. In the tribe Cichoriacee only one genus was studied, and 
so no conclusions can be drawn as to the constancy of the style 
characters. h 
So we find, that while the style characters like other charac- 
ters are of great value in some cases, in others they fail, and must 
be used in connection with some other characters in order to es- 
tablish tribes. 
_Finally, I desire to express my thanks to Prof. L. H. Pam- 
mel, for his supervision and direction of my work, and to Mr. W. 
Zmunt, for carefully retracing my drawings. 
EXPLANATION OF PLATES. 
Plate CXVIT. 
Figs. 1-5.— Vernonia Arkansana, DC. 1-3 style x 30; 4, portion of fig. 1 
enlarged x 60; 5, brush hairs x 500. 
Fig. 6.—Brush hairs of Z/ephantophus Carolinianus, Willd. 500. 
3 
