206 
James Small. 
The origin of Senecio from the Siphocampylus-Centropogon group 
of the Lobelioideae somewhere between the forests of the Amazons 
and the heights of the Andes has been proved as clearly as is 
possible without actual ocular demonstration of the process. The 
evolutionary processes involved in this origin are shown to be 
orthogenetic saltation and epharmosis, and the date of the event 
is indicated by the geological evidence to be the late Cretaceous 
Period and approximately the same as the date of the first upheaval 
of the Andes. 
The Senecioninse consist of a group of genera closely related 
to Senecio. The detailed evolution of the genera in this sub-tribe 
is interesting, but is reserved, together with the detailed generic 
evolution of the other tribes, for future contributions. The facts 
of floral morphology and geographical distribution which are 
available should be supplemented by other data before any attempt 
is made to deal with the details of phylesis in the smaller sub¬ 
divisions of the family. It will be sufficient for the present to 
suggest possible basal or transitional genera where these are 
clearly indicated. 
Liabuin is the primitive genus of the Liabinse ; this is shown 
by the floral morphology and geographical distribution. This genus 
maybe regarded as the Gynura of America, the type Villa style 
of Gynura being very similar to the type III style of Liabum; other 
characters also show a parallelism. It is interesting to note that 
these two genera flourish in the same latitudes, the one in America 
and the other in the Old World. The transition from the discoid 
species of Liabum to V ernonia is more a matter of the corolla 
colour and the phyllotaxis of the cauline leaves than anything more 
serious. 
In Chapter II, E, the very close proximity of one genus of the 
Tussilagininae, Cremanthodium, to Senecio is discussed. This 
sub-tribe is probably not monophyletic in the sense that a single 
primitive genus in the group has given rise directly or indirectly to 
the other genera ; it is probably monophyletic in the sense that all 
the primitive genera have arisen directly from Senecio. Thus 
Cremanthodium is a comparatively recent genus which has arisen 
directly from the Ligularia section of Senecio. It is very probable, 
although less certain, that Petasites also arose in the same Asiatic 
region, but at an earlier date, from Senecio and Ligularia, and that 
it has given rise to the other genera of the Tussilagininae. Alciope 
in South Africa is probably a third offshoot from Senecio. The 
