28 
James Small. 
several variations of the bilabiate and tubular corolla forms; the 
disc and ray arrangement occurs here also, but never in the 
Cynareas. The tubular corolla in the Mutisieae is frequently very 
deeply lobed and the posterior indentation may be deeper than the 
others as in Helenium autumnale. The bilabiate forms in this 
tribe usually have the anterior lip with three teeth or lobes and 
the posterior or upper lip takes on a variety of forms (Figs. 12-15). 
The Cynareae have usually a regular, tubular corolla but the outer 
florets of the capitulum may be enlarged to form a ray; the 
corolla then becomes more or less irregular and the number of 
lobes increases to seven or eight in some species. These ray florets 
also show a tendency to become irregular or bilabiate. The 
Cichorieae invariably have the truly ligulate corolla in all the florets 
of the capitulum. This corolla is always strap-shaped with five 
teeth. The florets towards the centre of the capitulum have the 
corolla closed to form a tube with the adjacent edges of the 
posterior petals tightly adpressed (Fig. 21). This is quite different 
from the aestivation of the bilabiate ray florets in which one side 
of the corolla overlaps the other (Fig. 20) before it unfolds to form 
the ray of the capitulum. 
The Cichorieae in this as in many other characters are distinct 
from all the other tribes, and the number of mutations which occur 
in the Compositae gives a basis to the suggestion that the Liguliflorae 
are monophyletic, derived comparatively recently from the Sene- 
cioneae by mutation. Only in this way can one account for the pollen 
grains (2) as well as the corolla, stamens, style and even some 
nuclear details being of one peculiar type throughout the tribe. It 
is interesting to note also that Senecio vulgaris sometimes shows a 
somewhat similar type of pollen grain occurring in a small 
proportion among pollen of the Tubifloral type (Fig. 23). De Vries 
(33) and Trow (31) have shown that the ordinary ray floret is liable to 
appear or disappear quite frequently so that it is no matter for 
surprise if the ray has disappeared in the Eupatorieae, Vernonieae 
and Cynareae. De Vries describes not a few mutations of various 
kinds in the Composite. Trow describes the origin by mutation of 
a fimbriate corolla in Senecio vulgaris and his explanation of the 
factors involved could well be applied in the case of the Cichorieae. 1 
Then if such a factor, probably a recessive, for true ‘ ligulateness ' 
does exist, it would furnish another explanation of those rare cases 
1 The suggestion made by Trow that the absence of the fimbriate character 
is a function of the environment as well as the factor, f, is interesting in connec¬ 
tion with a case recorded by Molliard (21). 
