206 
Hill and de Fraine. — On the 
This cotyledon showed no external signs of a division, but the examination 
of the sections showed that there were, throughout its whole length, two 
distinct bundles, well separated one from the other, the structure strongly 
recalling the condition which obtains in Ephedra (Diagram 5, Fig. 6, a). 
The two strands gradually approached one another and entered the axis as 
entirely distinct endarch structures : no bifurcation took place, but the 
xylem of each rotated towards the other and outwards ; thus the exarch 
position of the protoxylem was assumed. The phloem of each strand 
fused with the adjoining bast derived from one of the other seed-leaves 
b and c , the bundles of which showed the essential rearrangement of the 
vascular tissues while still contained within the seed-leaves (Diagram 5, 
Figs. 7 and 8). 
Pinus montana , var. gallica . 
The majority of the seedlings examined had four cotyledons, one only 
possessed three. 1 
Series A. The transition in this plant followed, on the whole, a normal 
course. It is only necessary to draw attention to two features. In one 
Diagram 6. Pinus montana, var. gallica . 
seed-leaf, the bifurcation of the phloem and rotation of the xylem took 
place, not within the seed-leaf, but during the inward passage towards the 
centre of the axis. Another cotyledon-trace showed this rearrangement of 
the vascular tissues within the seed-leaf, but the division of the bundle was 
unequal (Fig. 3, PI. XV). 
Series B. Two of the three cotyledons showed signs of splitting 
at their apices. Each of these seed-leaves had two vascular strands well 
separated one from the other. The behaviour of the bundles of one of these 
cotyledons was exactly the same as those of the seed-leaf a of Pinus 
contorta , var. Murrayana , Series K (Diagram 5, Figs. 6-8). The changes 
exhibited by the pair of bundles of the other cotyledon are illustrated 
in Diagram 6, from which it will be seen that the two strands (a and a') 
approach one another and, at the same time, a undergoes bifurcation of the 
1 Masters (loc. cit.), stated that the species has five cotyledons. 
