14 
James Umall. 
Rather isolated developments of local species occur in Australia 
and New Zealand, which are connected by S. lautus , Forst., and 
5. odoratus , Horn. 
The six Javan species and the five Phillippine species indicate 
the two probable paths for the Australian supply of Senecio, the 
one from India via Burma and the Malay Peninsula and the other 
from China, via the Phillippines and East Indies (cp. Gibbs, 31, 
on New Guinea as the source of Australian types). 
Ecology. 
It will be clear from the above considerations that the 
regions of concentration for local species lie along the paths of 
migration as shown by widespread species, and that both are more 
or less co-extensive with the 3,000 ft. level throughout the world. 
The reason is to be sought in the aut-ecology of the genus, but as 
this forms the subject of a more extensive account now being pre¬ 
pared it will be sufficient to indicate briefly some of the more 
salient points, 
The genus Senecio includes herbaceous annuals, biennials and 
perennials, which may be anything from aquatic to xerophytic in 
structure, also semi-shrubby and shrubby forms, which are erect or 
climbing, and trees of various growth forms. 
The weedy type is the commonest and occurs in all the 
mesophytic habitats, but there are a number of distinct types 
which are characteristic of the regions where they occur. In 
common with many other Composite these weedy species of 
Senecio show a general tendency to develop a single, rather large 
capitulum, instead of the common branched inflorescence, as the 
altitude of the habitat increases. This type, sometimes called the 
Arnica type, occurs along the very high regions of the Andes and 
Cordilleras, and also lower down in the Arctic region. S. Pseudo- 
Arnica and 5. frigidus have this uni-capitulate habit, while 5. 
resedifolius is similar but smaller and more like Beilis perennis. 
Along the west Thibetan path this Arnica type is replaced by 
species which with the same general structure are of ranker 
growth with medium-sized capitula arranged in corymbs. Along 
the east Thibetan path the Arnica type is replaced by larger 
species with racemes of large capitula. Further south these 
two types are replaced by less rank but similar growth forms. 
The shrubby species of South America are scandent in Brazil 
but usually erect in the Andes, and show several peculiar types. 
