Origin and Development of the Composites. 2 1 5 
of the capitulum ! The Tussilagininae are, therefore, very intimately 
connected with the genus Senecio, which itself shows type VII styles 
not infrequently, and more rarely, as in some sub-sections of the 
Ligularia group, type VIII, thus leading up to type II in 
Cremanthodium. 
The Othonninae cannot be distinguished from the Senecion- 
inae by either styles or stamens, both being comparatively simple. 
The Senecioninae in both stamens and styles shows the 
characteristics of a primitive group. Type IV styles are combined 
in most genera with type 3 stamens, a simple and primitive pollen- 
presentation mechanism. Senecio itself, however, sometimes shows 
styles of types VII and VIII and sometimes stamens of types 4 or 
8 but these two elaborations rarely, if ever, occur in the same 
species. They are, indeed, associated with two very different habits. 
Other closely allied genera always show type VII or type VIII in 
their styles, others always show type XII styles, which type also 
occurs in some species of Senecio. 
It is not possible at this point to distinguish which is the more 
primitive of the two sub-tribes of the Vernonieae but most of the 
large genera with simple stamens occur in theVernoniinae. Vernonia 
itself shows both type 5 and type 10. 
In the Eupatorieae the style is of a uniform type as in the 
Vernonieae, so that the relative complexity of the pollen-presentation 
mechanism depends on the type of stamen. The simplest type of 
stamen occurs in the Piqueriinae and nowhere else in the family. 
That this is a reduced, not a primitive type, is rendered probable by 
its occurrence only in this small and somewhat specialised group 
and is proved by the series of forms previously figured (61, Figs. 3-6). 
The normal apical appendage as in Eupatorium cannabinnm (61, 
Fig. 6) becomes truncate and obviously reduced in Sclerolepis (61, 
Fig. 5) which is the genus in the Ageratinae next the Piqueriinae. 
In Adenostemnia viscosum (61, Fig. 4) and other species of the chief 
genus in the Piqueriinae the line of dehiscence does not extend to the 
apex of the anther when dehiscence is completed and the apical 
indehiscent region carries out the function of the ordinary apical 
appendage. In the other genera (61, Fig. 3) dehiscence is carried 
to the apex and the abortion of the apical appendage is complete. 
It is scarcely possible to distinguish at the present stage between 
the other two sub-tribes, but the complete uniformity in the stamens 
as in the styles of the Adenostylinae indicates a probably specialised 
group. 
