Davey .- — Seedling Anatomy of certain Amentiferae. 591 
In the species of Quercus examined, the vascular structure of the 
cotyledonary node and hypocotyl conforms to the hexarch type (Fig. 1, B). 
The cotyledon petioles contain three massive vascular strands, of 
which the central one is double near the cotyledonary node, while the 
laterals are usually not obviously so until they enter the axis. Here the 
usual triad grouping takes place in connexion with all the strands. The 
hypocotyl contains six protoxylem centres (two cotyledonary and four 
diagonal), each flanked by scattered tangentially placed metaxylem. The 
adjacent phloems of neighbouring triads approach each other. The pith 
is very large. Plumular traces are present in the cotyledonary node 
and for a short distance below it, interpolated between the cotyledon 
strands. 
Quercus robur . The hypocotyl and root show hexarch structure 
related to three strands in each cotyledon. 
In one seedling the central strand was very small in one cotyledon and 
was entirely absent from the other. Five triads were organized in the 
hypocotyl for a short time, but only the four diagonal ones persisted, 
and the root was tetrarch. 
Another individual showed extreme development of incurved traces in 
the cotyledon petioles. Irregularly grouped strands from the lamina came 
together, forming a much-extended central band with incurved ends and 
a pair of lateral strands in the form of more or less complete rings. Near 
the node the rings opened out and became organized as double bundles. 
Central protoxylem was not present above the node. The central band 
slowly became more compact and was resolved into a double bundle in 
which central protoxylem elements were present. These bands and rings 
consisted mainly of secondary tissue, the primary elements being very small 
and fugitive. 
Quercus Ilex. The seeds and seedlings are somewhat smaller than 
those of the other species described. 
In general the seedlings were hexarch, but the following modifications 
occurred. In some individuals, eight triads were present in the hypocotyl. 
These were arranged as in the double diagonal type. Each triad was con- 
tinuous with one of four strands in each cotyledon, and occurred as 
laterally placed pairs ; sometimes, however, the two innermost groups came 
together to form a single large central strand. A very small central strand 
was sometimes produced by the union of portions detached from the laterals. 
The root was diagonally octarch, as in Fagus sylvatica. 
In a few otherwise normal seedlings there was increase in the number 
of root poles from six to seven or eight. This always took place at some 
distance below the collet and was observed only in relatively old seedlings. 
Quercus Cerris. All the individuals examined followed the general 
hexarch type and showed no irregularities. 
