164 Blackburn . — On the Vascular Anatomy of 
There were only two lignified elements in connexion with the traces of 
the second foliage leaf, so that at a slightly older stage the woody tissue is 
almost entirely secondary. Except for these features the young seedling 
resembles Aquilegia , even to the angular divergence of the three bundles 
from each leaf. 
A . pyrenaicum was examined at an age intermediate between the two 
stages of A. Wilsonii. It appeared to be essentially similar. The foliage 
leaves are somewhat smaller than in the last species, and covered with short 
hairs. Tuber formation had just begun and was accompanied by large 
stores of starch in the cells. The primary wood of the vascular bundles 
consisted at most of two to three elements, and the rest was all secondary ; 
but, owing to the formation of definite medullary rays, the individual bundles 
are still clearly delimited. 
At the cotyledonary node the plumular strands are collected up into 
two fan-shaped bundles, the triple nature of which can only be distinguished 
higher up. 
A. Napellus is similar to A. pyrenaicum. 
Clematis. M. Sterckx 1 has described this genus in great detail. He 
takes C. Vitalba as the type, and describes all stages in the anatomy of 
the axis, treating the other species comparatively. 
In the adult plant the leaves are opposite and decussate. There are 
six large bundles in the stem, and a varying number of smaller ones alter- 
nating with them. The larger ones alone are directly continuous with the 
leaf traces. Each of the large bundles bifurcates just above the node, and 
the’ resulting halves fuse with the adjacent entering strands, of which there 
are six, three from each leaf. Thus the strands of one node are in position 
between those of the nodes above and below (cf. Equisetum). The smaller 
bundles are connected above and below with the half-bundles just mentioned. 
While the leaves in the adult plant are always opposite, in the seedlings 
of three species, C. Vitalba , C. Davidiana , and C. alpina , the phyllotaxis is 
two-fifths. 
Germination may be epigeal or hypogeal, and in some cases both con- 
ditions may be found in one species, e.g. C. orientalis. 
The seedling anatomy of the spiral forms strongly resembles that in 
Aquilegia , but that of the opposite-leaved forms is specialized in connexion 
with this habit. 
C. Vitalba. The cotyledons are slightly stalked and epigeal. The 
first few foliage leaves are ovate and long-stalked with irregularly serrate 
margins. The phyllotaxis is two-fifths and the internodes are very short (see 
Text-fig. 8). 
According to Sterckx it is not till about the fifteenth foliage leaf that the 
arrangement becomes opposite and decussate. 
1 Loc. cit. 
