542 MR, G. BENTHAM ON COMPOSITA. 
2. Europeo-Asiatic Region. 
Under the name of Europzxo-Asiatic or North temperate and 
Mountain region of the Old World, I would designate that vast 
area extending from the Atlantie to the North Pacifie, which has 
been so frequently adverted to as presenting a remarkable con- 
tinuity in the character of its vegetation through its entire length, 
a character fully maintained in respect of Composite. Its limits 
would at first sight appear to be more readily fixed than those of 
some other regions, although on investigation numerous difficulties 
occur. It should include all the mountain-races which inhabit 
the Pyrenees, the Alps, the Caucasus, and the Himalayas; but 
along the whole range it is often no easy problem to separate the 
southern races which have ascended or maintained themselves with 
or without specific modification in the warmer valleys, or the 
northern or mountain ones which, carried down to the lower 
grounds at their southern feet, have there become definitively 
established. At the eastern extremity, also, that intermixture of 
northern and southern forms which I have commented upon in 
recent Anniversary Adresses is exemplified in Composite, as in 
other orders, interfering with any definite line of demarcation. 
The region is rich in Composite. It has not, it is true, half 
the numbers of the Mediterranean; but it is richer than the 
corresponding American (United States) region, although less 
diversified. With a hundred more species, the genera are fewer 
by thirty ; and the local endemic monotypes can scarcely be com- 
puted at more than ten, unless, indeed, we consider as such a few 
species which have, on slight technical characters, been raised to 
that grade; and even among those ten none have so marked a 
character as some of the American ones. If, again, the Europxo- 
Asiatic species are numerous, averaging nearly ten to a genus, 
the varieties are still more so, and individual species, as well as 
the prevailing genera, have very large areas, many of them ex- 
tending from one end to the other of the region. This prevents 
the separation of a European from an Asiatie region which the 
presence of a few endemic genera in each might at first sight have 
suggested. 
Two small genera only are limited to Europe, Adenostyles and 
Homogyne ; the former, represented by a closely allied species in 
California, belongs to a tribe (Eupatoriacew) which is essentially 
American, although it be in some respects an outlying member 
tending towards the Cacalia group of the cosmopolitan Senecio ; 
