Origin and Development of the Compositce. 85 
whole but Siphocampylus shows a number of herbs with the 
common Senecio habit, while a number of the arborescent species 
of that genus are very similar in general appearance to some 
arborescent species of Senecio. We may also mention Isotoma 
senecioides (see 44, p. 66) with the habit of a weedy Senecio. 
The final test, that of geographical distribution, may now be 
applied. In the Lobelioideae there are six genera endemic in the 
Sandwich Islands, one in the Company Islands, and one in 
Madagascar. Of the other local genera one is Mexican, one extends 
from Abyssinia to South Africa, another from South Africa to 
Australia and three, Lysipomia , Hypsela and Rhizocephalum, are 
Andine. Isotoma has six species in Australia and one each in the 
West Indies and the Company Islands; Laurentia extends from 
North America to the Mediterranean and South Africa, and Lobelia 
is widespread, occurring in the Old World and in South America. 
The genera which show the best development of anther 
appendages, aggregation of the flowers, etc. are the three Andine 
genera and the remaining widespread genera. These are Pratia, 
which extends from South America to Australia and tropical Asia, 
Downingia, which extends from Oregon and California to Chili. 
Centvopogon and Siphocampylus , both of which extend from tropical 
South America to Central America and the West Indies. These 
last two genera have about 100 species each and show many of the 
above-mentioned tendencies. It should now be clear why the 
north of South America was taken in Chap. X as the centre of 
origin for Senecio, 
I will now try to help the student to visualise the origin of the 
first Senecio as a living, moving process—in fact attempt the kind of 
presentation which has already been advocated in this journal. 
This attempt being necessarily descriptive cannot be other than 
cinematographical, but with a little mental effort and a little study 
of Bergson (7, pp. 314—330) the student may be able to perceive 
the “ becoming ” from Siphocampylus to Senecio. It will be 
sufficient to say that the following is an attempt to present the 
origin of one definite kind of living organism from another definite 
kind of living organism as a normal, natural result of the actual 
living of the parent organism in a particular region. 
Let us suppose a certain species of Siphocampylus grows as an 
arborescent scrambler on the edge of the forest about the sources 
of the Amazons. It has already developed a racemose umbel as 
an inflorescence, the outer bracts remain more or less foliaceous, 
