402 MR. G, BENTHAM ON COMPOSITE. 
Rocky Mountains. Their constantly alternate leaves, their 
general habit, and, to a certain degree, their corollas, may indicate 
some approach to the Vernoniaceæ; but their styles and other 
most important characters are essentially Eupatoriaceous. 
3. Asteroidee. 
The vast tribe of Asteroides is neither so well marked as a 
whole as Vernoniacese and Eupatoriacee, nor yet is it well 
divisible into distinct groups. Nearly the whole of the 90 genera, 
comprising above 1400 species, pass into each other through ex- 
ceptional or intermediate forms ; and there are species if not genera 
closely connecting Asteroides with Inuloides, with Anthemidee, 
and with Senecionides. Of these four intimately connected tribes, 
comprising about half the known Composite, two, Asteroidew and 
Senecionidex, are cosmopolitan, the two others chiefly Old- 
World. 
The Asteroidew not being divisible into distinct subtribes, we 
may for geographical purposes consider a certain number of types 
with the various divergences from them, and then take up a few 
comparatively isolated forms. The principal of these types are 
Grangea, Bellis, Solidago, Aster, Erigeron, Conyza, and Baccharis. 
Six of them are eommon to the New and the Old World, the 
first two chiefly belonging to the Old World, the next four more 
numerous in the New, and Baccharis entirely American. The 
whole tribe affects chiefly temperate or mountain regions of both 
hemispheres, tropical Asteroides being comparatively rare. 
1. The Aster type.—Aster, taken in its most extended sense, 
ranges over the whole area of the tribe; but isolation has been 
ancient enough to admit of its having established special forms in 
different countries, which are now admitted as genera by most 
botanists. Aster itself, as we have limited it, forms a group of about 
250 species belonging to the temperate regions of the northern 
hemisphere, chiefly North American, a very few species rather 
abnormal descending along the western regions into South 
America, and a mountain form connected with a European and 
Asiatic one crossing the equator in Eastern Africa. These true 
Asters are herbaceous, usually perennial, often tall, though some 
mountain species are quite dwarfed or almost stemless ; the invo- 
lueres are usually broad, the heads heterochromous, the achenes 
flat, and the pappus copious. Among the modificationsjobserved 
within the genus as we now retain it which some asterologists 
