Origin and Development of the Compositce. 35 
The distinction between the ray florets of several tribes and 
the bilabiate florets of the Mutisieae is removed, making it more 
probable than ever that the latter tribe is a mere collection of 
bilabiate forms and not a natural tribe. 
The occurrence of many discoid forms and the predominance 
of yellow in the Senecioneae confirms that group as the basal 
plexus. The similarity in colour and the small change in the form 
and anatomy of the corolla in the Cichorieae confirm the position 
of that tribe. The similarity in form and colour of the corolla in 
the Calenduleae confirms the position of this tribe. The greater 
predominance of yellow in the Chrysanthemidinae suggests that this 
is the more primitive sub-tribe in the Anthemideae. 
The colour and form of the corolla in the Vernonieae and 
Arctotideae confirm the positions of the sub-tribes in these two 
groups, and the yellow of Ursinia adds evidence for the suggestion 
that that genus is the primitive one in the Arctotideae. The frequent 
disappearance of the ray florets in many tribes makes the origin of 
the Vernonieae from a rayed group like the Liabinae very probable, 
and the occurrence of several discoid genera in the Liabinae confirms 
that sub-tribe as the source of the Vernonieae. Indeed, Gongro- 
thainnus , one of the Liabinae according to Bentham, is placed in the 
genus Vernonia by Hoffmann. 
The occurrence of filiform florets in the lower sub-tribes of 
the Inuleae and in a few genera of the Astereae is accounted for 
by the plasticity of organisation proved for the outer florets of 
the capitulum. The occurrence of the same type in Homogyne 
(Tussilagininae) shows that the tendency towards the reduc¬ 
tion of the bilabiate corolla to the filiform type is already 
present in the Senecioneae, finding expression in two separate lines 
of evolution. The rayed condition in the higher Inuleae may be 
regarded as a reversion to the general type, but it is possible that 
this tribe is not monophyletic but diphyletic, in which case the 
Cynareae may have arisen either from the Buphthalminae as pre¬ 
viously suggested, or from the Plucheinae through forms such as 
Cavea (74a). Other data are required to elucidate this point. 
The derivation of the Cynareae from the Bupthalminae is 
partially confirmed by the colour, yellow in a few Centaureinae and 
in the parent sub-tribe. The relative positions of the sub-tribes of 
the Cynareae are also confirmed by the distribution of colour in the 
tribe. 
