662 Proceedings of Royal Society of Edinburgh. [sess. 
ring ; a and b in the same section (fig. 20) are cut obliquely as they 
pass to the first pair of leaves. 
A longitudinal radial section (fig. 18) in the vertical plane con- 
taining D E (fig. 21) shows bundles a and b in longitudinal section, 
while one slightly tangential shows c and d or e and / cut trans- 
versely on their way out to the vascular cylinder. Moreover, in 
the longitudinal radial section through some other diameter of the 
embryo than D E, procambial strands, giving rise later to c, d , e, 
and /, could be seen in the act of development in the region just 
below the growing point (fig. 23). 
Hence, in the embryo the six bundles a , b, c, d> e, and / are 
developed just below the growing point, and extend downwards 
to the hypocotyl and upwards to the first pair of leaves ; the 
bundles a and b being ahead of the others in their development in 
point of time. It seemed also probable that the branches between 
these bundles and the adjacent cotyledon traces were a later 
downward development of these six. 
This idea was confirmed by an examination of the first branches 
(figs. 10 and 11) in the very young germinated specimen mentioned 
before (fig. 22). Of the six bundles a, b , c, d , e, and f it was only 
in a and b that thickened xylem elements were present ; at no 
level were they to be seen in the later developed bundles c, d, e, 
and/. 
Following the branches which fuse to form the bundle a up 
from their connection with the cotyledon trace, they are seen at 
first to have no thickened elements at all. Higher up, thickening 
on the xylem vessels occurs, the number of such vessels and the 
amount of thickening increases till the branches anastomose and a 
is formed. 
Hence the portion of the branch in connection with the cotyledon 
trace is the youngest, and the branch itself is a downward develop- 
ment from a, and not a branching in development from a cotyledon 
trace. 
We conclude, therefore, that the foliar bundles a, b, c , d, e , and 
/ going to the first pair of leaves are developed in a ring cor- 
responding to the first node after that of the cotyledons, at a time 
when the position of the ring in question was just below the grow- 
ing point, and in the same way the bundles going off to the leaf 
