Origin and Development of the Compositce. 33 
less probable. A study of Tables VI and VII shows that a lower 
position is possible and more data are required. 
E. Anatomy of thk Corolla. 
For an account of the complete anatomy of the various types 
of florets the reader is referred to a previous publication (76) and 
the literature cited there. As the literature has already been dis¬ 
cussed (Section A) it is necessary to give only a brief summary of 
the facts in their bearing on the general problem. 
Tubular Corolla. There are five conducting strands which 
do not occupy the position of the midribs of the constituent petals 
hut are situated along the fused margins (Fig. 9, 1). At or near 
the base of the corolla these strands, which originate in the upper 
distributive centre (see 76, p. 518), divide tangentially to give the 
staminal bundles. These pairs of bundles occupy the narrower 
part of the corolla, and the staminal bundles pass out into the 
filaments where these become free, usually at the base of the 
campanulate part of the corolla (cp. Fig. 9, 19). 
The corolla strands continue upwards and divide radially at 
the bases of the corolla lobes. These half-bundles then arch over 
and fuse with adjacent halves, giving five arches along the 
margins of the five lobes. There is little or no variation in this 
type of corolla anatomy. 
Ligulate Corolla. At the base of the corolla five strands arise 
from the upper distributive centre as in the above, but the behaviour 
of the posterior bundle is different. Near the base it divides, first 
tangentially to give the staminal bundle, and then immediately or a 
little higher up it divides radially to give two bundles which run 
along the margins of the ligule (cp. Fig. 9, 21 and 3). The other 
four bundles, some distance from the point at which they give the 
staminal strands, divide radially at the bases of the corolla lobes, 
bend over and fuse to give arches as before. The marginal bundles 
behave as the half bundles which they really are, and fuse with 
adjacent halves. The only real difference, therefore, between this 
and the tubular type of anatomy is that the radial division of 
the posterior bundle takes place earlier in the ligulate corolla. 
There is no recorded variation in this type of anatomy. 
Bilabiate Corolla. The vascular supply of the bilabiate corolla 
varies with the width of the anterior lip as a rule, and the variations 
seem to be the result of a response to the physiological needs of 
