Origin and Development of the Composites. 
South America, and the Cichorieae in the Mediterranean region. 
The present investigation, however, shows that the distribution of 
this genus is quite in accordance with previous suggestions. 
* 
Method. 
In dealing with the Composite the world may be divided into 
a few large regions, which do not always correspond to the regions 
delimited in the study of other families. 
America is divided thus:— 
U. S. A. region:—including Canada and Alaska. 
Mexican region:—including Central America andCalifornia. 
West Indian region:—including all the West Indian 
Islands in the widest sense, 
Andine region :—including west tropical South America. 
Brazilian region :—including east tropical South America. 
Chilian region:—including extra-tropical South America. 
The rest of the world is divided thus :— 
Bur-Asiatic region :—including north and central Europe, 
Siberia and the eastern parts of subtropical Asia. 
Mediterranean region:—including south Europe, north 
Africa and the western parts of subtropical Asia. 
Tropical Asiatic region:—including India south of the 
Himalayas, the East Indies and the Malay 
Archipelago. 
Tropical African region. 
South African region:—including extra-tropical South 
Africa. 
Australian region :—including the Australasian islands. 1 
These regions serve for a preliminary analysis of distribution 
and will be frequently referred to later, but in the case of Senecio 
a detailed investigation was made. An alphabetical list of the 2300 
species of Senecio in the Index Kewensis and its Supplements to 
1910 was made, including amongst other data the habitat as there 
recorded. A number of floras and papers (84-135)and the Herbaria 
at Kew and Edinburgh were then examined for further details. 
During this investigation about 50 new species were added to the 
list, so that it is more or less complete. The results of this study 
are naturally too bulky to be included in the present condensed 
1 A somewhat similar division for mammals is made by Sclater (62) and 
it is interesting to note that his Cape sub-region connects directly in East 
Africa with the Saharan sub region ; and that his Western or Arid sub-region 
includes most of Mexico and the western U.S.A (see below on Paths of 
Migration). 
