James Small. 
274 
styles, but by the same phenomenon the tribe is shown to be more 
homogeneous. The occurrence of types A and B, as well as C, but 
no irritable style in Urs'tnia is very interesting as that genus was 
suggested (Chap. 11, E) as the primitive genus in the tribe. 
The two sub-tribes in the Anthemideae again cannot be 
distinguished. 
The large development of irritability (90% or 18 out 20 species) 
in the Inuleae is quite in accordance with the suggested derivation 
of the Cynareae from that tribe, and the marked movement in 
Odoniospermum and the occurrence of the B type in Buphthahuum 
also support the same suggestion. Only one of the Cynareae 
examined ( Centaurea pulcherrima ) showed no irritability, but the 
pollen-presentation is somewhat anomalous, and further investigation 
is required. Irritability is highly developed in this tribe, and the 
type A movement is combined in a marked degree with the lateral 
movement of the C type, so that the advanced position of the 
Cynareae is maintained. 
In the Mutisieae it was suggested that the Nassauviinae was the 
primitive group, and this is supported by the occurrence of the A 
and B types in Moscharia of that sub-tribe and the development of 
the explosive mechanism in Perezia and the Gerberinae. 
In the Astereae the absence of the A type from the Homo* 
chrominae and the Conyzinae may be taken as the forerunner of the 
complete absence (by disappearance) of irritability in the Eupatorieae, 
or it may be that the Heterochrominae with type Ais the higher group* 
The development of the A type in the Heterchrominae confirms that 
group as one in advance of the Senecioninae, while the absence of the 
A type in the Bellidinae is to be explained by its relative nearness 
to the primitive stock. 
The Heleniese are particularly interesting. On account of their 
comparatively advanced stamens (types 4-6) the Heleniinae were 
placed above the Tagetinae (type 3), but were derived from the stock 
before the latter on account of the simplicity of their styles (type IV) 
as compared with the Tagetinae (types VII-VIII). Now, while the 
latter shows no irritability, the Heleniinae do so to a large extent. 
The other sub-tribes were derived from the Tagetinae, and show no 
irritability. 
In the Heliantheae the A type movement, which is undoubtedly 
distinct from the C type, occurs in the Coreopsidinae and Melam- 
podiinae, two sub-tribes which are placed in the same line of 
evolution in the original phyletic scheme. 
We therefore come to the conclusion that the evolution of 
the sub-tribes suggested in Fig. 7, Chap. II, is confirmed by the 
