Davey. — -Seedling Anatomy of certain Amentiferae , 583 
JUGLANDALES. 
Juglandaceae. This family includes both hypogeal and epigeal forms, 
in all of which the cotyledons are deeply bifurcated, the resulting halves 
being again divided. 
All the species of Jug tans and Carya examined possess large seeds and 
robust seedlings. The bifurcation of the massive folded cotyledons extends 
down to where the lamina merges into a broad flattened petiolar region. 
There is a very short thick hypocotyl and a stout primary root. The 
plumular axis lengthens at an early stage and bears scales like rudimentary 
leaves which show gradual transitions to the mature form. 
Juglans nigra. The cotyledon petioles each contain a small central 
bundle flanked by two pairs of large lateral strands which supply the 
four lobes of the lamina. These lateral strands are extended and some- 
what incurved, and smaller branches from the lamina sometimes unite with 
Fig. 6. Juglans nigra. A. Cotyledonary node. B. Hypocotyl. C. Root. px. = protoxylem ; 
ph. — phloem. Arrows show direction of cotyledonary and intercotyledonary planes. 
them in such a position as to produce inverse orientation. This does not 
extend into the node. 
The central cotyledonary trace enters the axis in the cotyledonary 
plane and is resolved into a double bundle. The adjacent laterals approach 
each other and enter as a more or less compact group in the diagonal 
planes. The intercotyledonary poles are occupied by the traces of the first 
two plumular leaves. Each consists of a central protoxylem group flanked 
by metaxylem, beyond which are two divergent phloem groups (Fig. 6). 
The structure is that of the triad unit considered by Dr. Thomas 1 to 
be characteristic of cotyledonary and probably also of plumular traces. 
The triad arrangement is continued upwards in the epicotyl until 
the exit of the leaf-traces as double bundles with loss of their central proto- 
xylem. In the short hypocotyl, root poles are organized in the cotyle- 
1 loc. cit., p. 732, and Text- fig. 28, p. 716 ( Draba Aizoon ). 
R r % 
