198 
Hill and de Fraine. — On the 
Towards their bases the seed-leaves fuse together to form a particularly 
well-marked tube, on the inner side of which foliage leaves are inserted, 
which indicates that, in the seedling, the apex of the stem is depressed. 
Cedrus atlantica . 
Series A. The seed-leaf-traces enter the hypocotyl and gradually 
converge towards the centre, forming a closed ring of vascular tissue with 
the protoxylem groups in an endarch position. The transition in this 
species, and also in C. Deodar a, is, in essentials, similar to that in Abies 
pectinata and species of Picea. It is, however, slower than in many of the 
preceding and foregoing plants. Eight of the bundles form four pairs, and 
the protoxylems of the vascular strands of each pair rotate towards one 
another and outwards, so that ultimately a tetrarch root-structure results, the 
phloem being interrupted opposite the exarch protoxylem masses. 
The ninth bundle was much slower in its movements than the rest ; 
ultimately it converged towards, and fused with one of the strands lateral 
to it, and its protoxylem also showed indications of an outward rotation. 
The fate of these particular elements was extremely hard to trace, for the 
adjoining bundles had already formed a pole of the root and their metaxylems 
were very compact. However, the appearances warrant the assumption 
that the protoxylem of this ninth bundle fused with the same tissue of the 
lateral strand mentioned above, thus this particular strand played the part 
of the bundle of a subsidiary cotyledon ; but, at the same time it showed 
characters usually associated with the trace of a half-cotyledon. 
Series B. This seedling had ten cotyledons, the bundles of which 
behaved in the same manner as the majority in Series A ; six bundles 
paired to form the poles of the triarch root, and the remaining four played 
no important part in the transition, and are therefore to be classed as 
subsidiary. 
One other individual (Series C) was also examined, but the vascular 
ring formed by the eleven cotyledonary bundles and the intervening 
plumular traces was so compact as to make it impossible to follow the 
changes with any degree of satisfaction. It is probable that of the eleven 
cotyledons, eight were half-cotyledons and three subsidiary ; the resulting 
root-structure was tetrarch. 
Cedrus Deodar a. The number of seed-leaves is eleven, and the transi- 
tion follows seemingly precisely that obtaining in C. atlantica . We add 
the slight qualification because the cotyledonary bundles are so numerous, 
and, in the hypocotyl, are situated so closely together that it is impossible 
to identify them with absolute certainty. 
In the seedlings examined, the resulting root-structure was pentarch, 
which in one case became reduced to tetrarch. 
