4 BOTANICAL GAZETTE [JANUARY 
the collateral structure which is characteristic of all the bundles of 
an internode. Further down in the node, the bundles of the leaf- 
trace enter the central cylinder and the smaller of these anastomose_ 
with branches of the nodal complex, and then turn outward to run 
down through the internode as cortical bundles. The larger leaf- 
trace bundles behave as in A. sativa. 
In Leersia oryzoides it may plainly be seen from a series of sections, 
that as each of the smaller leaf-trace bundles enters a node, it is 
joined by two small bundles from the nodal complex, and this rein- 
forced bundle proceeds downward through the sclerified cortex. 
Whether the smaller leaf-trace bundles run down through the 
cortex, or in the outer region of the central cylinder of an internode, 
cannot in all cases be determined with certainty, for the boundary 
of the central cylinder is often poorly marked, and the cortex may 
be a very narrow zone. Or the boundary of the central cylinder 
may be marked by a narrow sclerenchymatous ring, and the bundles 
may lie along this, projecting either towards the inside or the outside. 
But the position of these bundles inside or outside the central cylinder 
appears to be a matter of indifference, and in either case they pursue 
a different course from that of the larger bundles. In a general 
way it may be stated that the smaller bundles of the leaf-trace, after 
fusing with bundles from the nodal complex, run downward through 
the next succeeding internode in the cortex or at its inner border, 
and at the next node below join with the bundles of the central 
cylinder. Species to which this statement applies are: Zizania 
aquatica, Leersia oryzoides, Avena barbata, A. sativa, Panicularia 
americana, P. nervata, Agropyron caninum, Elymus americanus, 
Triticum sativum. 
The course of the leaf-trace bundles in the grasses, as here de 
scribed, differs in several respects from the course of such bundles 
in other families, even in so closely related a family as the sedges, 
recently described by PLowMAN (11). VaN TIEGHEM’s second class 
of cortical bundles (6, p. 751) corresponds the most closely, and is 
thus described: “Le faisceau médian de la feuille, qui en prend 
trois, entre directement dans le cylindre central, tandis que les deux 
latéraux descendent dans l’écorce pour n’entrer dans le cylindre 
