34 
James Small. 
the corolla. Thus in the ray florets of Tussilago Farfara there 
are four bundles at the base of the corolla, the posterior one is short, 
while the two lateral strands end blindly in the tissue of the margin 
of the very narrow anterior lip. The one anterior bundle seems to 
be sufficient to supply the needs of the very narrow corolla. In 
the ray florets of Calendula vulgaris there are again four bundles, 
two small lateral strands occupying the margins of the anterior lip, 
and two larger strands occupying the fused margins of the anterior 
and two lateral petals (Fig. 9, 2). These form arches at the top of 
the corolla as in the previous types. The Calendula type may be 
taken as the usual one for a ray floret, but there are many varia¬ 
tions. The anterior lip may be four-Iobed with five bundles (two 
marginal), or it may be broad and three-lobed with a vascular 
supply for four lobes, or it may be narrow and two-lobed or entire 
with a vascular supply for three lobes, i.e., four bundles with two 
marginal. 
Where the anterior lip is broad the strands tend to increase in 
number, the accessory strands frequently developing in the positions 
of the midribs of the three petals, giving a total of seven. The 
number in the wider part of the lip is frequently increased to 
twelve and more by branching of the four primary strands or of the 
three midribs. Usually these accessory strands end blindly in the 
tissue of the corolla, only the primary strands fusing to form the 
marginal arches at the tip, but fusions of various kinds may take 
place. 
According to a figure by Hildebrand (36, Plate V, Figs. 22-23) 
the vascular supply of the irregularly bilabiate corolla in Centaurea 
montana is similar to that of the tubular corolla with the radial 
divisions occurring at irregular heights. 
The known facts are, therefore, that the anatomy of the tubular 
andligulate corollas is constant, and that of the bilabiate corolla is 
as variable as the external form of that type. 
F. Phylogenetic Significance of the Corolla. 
When all the foregoing facts concerning the corolla are con¬ 
sidered they are found to confirm the previous phyletic suggestions 
in all except a few points. 
The primitive nature of the tubular floret, which is shown 
clearly by Uexkiill-Gyllenband (Fig. 4, Chap. II) is confirmed by 
the study of the development and vascular anatomy of the corolla 
and the various lines of evolution shown in Fig. 4 follow com¬ 
paratively closely the scheme in Fig. 7. 
