AFFINITIES OF DAVIDIA INVOLUCRATA. 309 
composite bundles according as they are near to or away from the periphery. In fig. 2 
the bundles are anastomosing. In fig. 4 the groups of bundles seen in figs. 1, 2, and 3 
have lost their individuality in four small masses of vascular tissue which form a part 
of the toral plexus (figs. 5, 6). 
The vascular tissue of the peduncle consists, below the point of insertion of the bracts, 
of a cylinder of closely adjacent bundles. Above the insertion of the bracts, four, five, 
six, or seven of these become prominent, projecting outwards a little from the ring (the 
behaviour varies). When there are six of these, three of them point towards one bract 
and three towards the other (the two bracts are not directly opposite one another), At 
the same time the axial cylinder, now six-rayed, becomes slightly one-sided, retaining 
this character throughout peduncle and torus. The course of the cylinder is oblique in 
the torus, due to the bulging of one side. It receives in the torus the mass of vascular 
tissue from the stamens. The vascular ring of the obliquely situated hermaphrodite 
flower is inserted on the oblique end of the cylinder. These points are illustrated by 
figs. 6 to 14. In this series four bundles project from the axial cylinder (fig. 10). 
Fig. 8 represents a section through the middle of the torus showing the vascular plexus. 
The lines extending inward from the periphery represent the vascular tissue of the 
stamens inserted at that level. 
Some of the staminal vascular tissue projects downwards into the top of the peduncle 
and becomes gradually aggregated into three peduncular bundle-groups on each rayed 
side of the cylinder in the torus. The middle group of each set of three is at first 
associated with the projecting bundle of the axial cylinder opposite it, and this 
association may continue some millimetres below the torus. The six little groups become 
ultimately free in the cortex of the peduncle as more or less irregular, slender cydinders 
as far as the bracts. Just above the insertion of these organs, the appearance of the 
groups in transverse section is that of vascular arcs with xylem inversely orientated. 
The many bundles of each bract unite at the sessile base into a three-bundled trace. 
The bundles of the trace enter the peduncle with their xylem normally orientated. 
Each trace becomes confluent with the three opposed inversely orientated arcs on its 
particular side and does not become attached to the axial cylinder. A vertical section 
through a confluent trace-bundle and are shows that they converge to a point, the opposed 
xylems being connected at an acute angle within the surrounding phloem. The bundle- 
groups can be distinguished in fig. 9, which represents a section from the base of the 
torus; a little lower the bundle-groups are distinct (fig. 10), but the median bundle 
of one side only is confluent with the corresponding projecting bundle of the axial 
cylinder. Below this level the groups become are-shaped as explained above. The 
bundles of the bracts are shown collecting into the trace-bundles which become 
confluent with the peduncular ares in figs. 12 and 13. : : 
The vascular structure of the inflorescence varies considerably in detail. Rarely 
there are less then six cortical peduncular bundles. There is also variation in the 
attachment of these bundles to the vascular axis; but the lateral ones join it usually in 
the torus. 
