522 MR. G. BENTHAM ON COMPOSITA, 
Vernonia, thirty-one of Eupatorium, ten of Mikania, and six or 
seven each of a few others ; but the number of Mexican or South- 
American genera represented in the islands by single or only by 
two or three species is sufficient to give, as a general average, not 
quite three to a genus in Cuba, and rather more than three in the 
British Islands; or if the whole of the islands, as far as known, 
are taken into account, the average is brought up nearly to four 
species to a genus. 
The endemie genera of the islands consist generally of herba- 
ceous aud often small species; where shrubby they belong to 
groups which are elsewhere shrubby, and the species of genera 
common to other countries are not more shrubby than their con- 
tinental congeners. Narvalina, however, may be exceptionally 
regarded as a shrubby representative of the herbaceous genus 
Bidens. There is no tendency to the arborescent forms of the 
more isolated islands of the Pacific and Atlantic Oceans. The 
mountainous islands of Cuba and San Domingo have more the 
character of detached fragments of a continental mountain-chain 
which have preserved the remains of a very varied flora, than of 
really isolated islands that have through a long course of ages 
modified such races as may have been casually brought to them 
under former physical conditions. 
4, Andine Region. 
The Andine or west tropical region of South America is but 
vaguely defined for our present purpose. It is a mountain-tract, 
connected in the north with the Mexican, to the east with the 
Brazilian, and to the south with the Chilian region, including 
generally the Columbian, Ecuadorian, Peruvian, and Bolivian 
States; but the bordering districts on each frontier are among 
_those of which the vegetation is, perhaps, the least known to us, 
thus depriving us of the data necessary for determining not only 
what are the precise limits of the region, but even whether any 
such can be assigned. The statistics of its Composite are thus, 
as yet, very uncertain. With a marked general character, it 
contains also numerous species of the great and widely diffused 
American genera Vernonia, Eupatorium, Stevia, Mikania, and 
Baccharis, as well as of the cosmopolitan Senecio. Its own genera 
are connected sometimes with the Mexican ones to the north, 
sometimes with the Chilian ones to the south, or with the Bra- 
zilian to the east; and some of those common to Mexico aud 
