234 Origin and Development of the Composites. 
By the time the middle Pliocene was reached most of the sub¬ 
tribes of the Compositze had been differentiated and events occurred 
only in rather outlying regions. In Australia the Helichrysum line 
developed the same “end product” as the above groups in the 
reduced, few-flowered, aggregated capitula of the Angianthinae. In 
South Africa the main stock of the family, the Senecionime, 
retaining its vitality to the last, gave off the Othonninae by the 
fusion of the periclinal bracts. The only later sub-tribe to arise 
was the small group Gundeliinae, another few-flowered, aggregated 
“ end-product,” which as mentioned above was produced in the 
same region from the Berkheya line in the upper Pliocene. 
The upper Pliocene and the succeeding geological period were 
characterised by generic, specific and varietal differentiation rather 
than by the origin of larger groups. This is probably due to the 
short period of time which has elapsed since the middle Pliocene 
and, perhaps even in a greater degree, to the more settled climatic 
conditions of the earth as a whole. 
It will be seen that a few fundamental tendencies or ortho- 
genetic lines, largely if not entirely due to epharmonic variation, 
can be traced throughout the various tribes in their wanderings 
over the surface of the earth during the Tertiary evolution of 
climate. Little else is required to account for the main variations 
in form and physiology of the Composite and that little can be 
supplied by mutational phenomena such as we are accustomed to 
at the present time. 
This is the story of the Composite in time and space and it is 
hoped that what has been lost in scientific accuracy has been 
regained to some extent in the coherence of the narrative. In any 
case the strictly scientific syhantherologist is referred for facts to 
the preceding chapters and he can neglect and forget this attempt 
to bring a real, living picture of the origin and development of the 
Compositae before the mind of the ordinary student. 
