175 
A Comparative Study of the Styles of Composite.* 
By J. S. CHAMBERLAIN. 
(Plates CXVII-and CXVIII.) 
The order Composite contains more species than any other 
order of the flowering plants. Bentham’ estimated the number 
of species known to him at nearly ten thousand. They are 
distributed in seven hundred and fifty genera, collected into 
thirteen tribes. 
The two hundred and thirty-five genera native to North 
America are distributed in eleven tribes, and according to Dr. 
Gray* comprise one-eighth of the Phznogams of the continent. 
Although the order contains so many species, it is so remarkably 
distinct and uniform throughout that a species is seldom wrongly — 
referred to or excluded from it. 
But to correctly place these ten thousand species in their 
proper genera, and these in their proper tribes, has been an im- 
mense undertaking for systematic botanists. It has been neces- 
sary to use characters derived from almost every part of the flower, 
differences in the inflorescence, corolla, pappus, appendages of the 
anthers, style, sexual differences, etc., many of which in other 
orders are considered of oniy secondary importance. 
Linnzeus, who arranged the Compositz into four great tribes, 
based his classification on sexual differences. Henri Cassini 
undertook a revision of the order, and in his classification made 
use of the style characters for the first time. Lessing! and De 
Candolle> made revisions of the order. They, more than Cassini, 
made use of the style characters. Great and valuable work has 
been accomplished by Dr. Gray, who in his various works on 
North America Botany has made use of the style characters in 
* Among the most convenient characters for separating tribes of the Composite 
is the structure of the style, but teachers seldom use this. With the hope that 
teachers will use this character more generally Mr. Chamberlain has studied in 
my laboratory the principal tribes and genera in Gray’s Manual. The results of his 
labors are presented here.—L. H. PAMMEL. 
- ' Notes on Composite, p. 336. 
2 Synoptical Flora of North America, p. 49. 
3 Opuscules Botaniques. 
4 Syn. Generum Compositarum. 
_ 5 Prodromus. 
