308 Brooks and Stiles .— The Structure of 
The axis of the cone, as seen in transverse section, contains a ring of 
collateral vascular bundles of the usual structure. No trace of centripetal 
xylem could be found, such as is present in the axis of the male cone of 
Saxegothaea (17). Each vascular bundle is accompanied by a single resin 
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canal outside the phloem, but it seems to be the general rule that these 
resin canals are not functional, for in most of them no distinct epithelial 
layer could be seen. On the other hand, resin cells are frequent throughout 
the fundamental tissue. A single vascular bundle, consisting of a few 
tracheides and phloem elements, passes out to each sporophyll. It arises 
by division of one of the axial bundles, the plane of division being radial; 
the two derived bundles lie side by side before one of them passes out to 
the sporophyll. The tracheides in the sporophyll are somewhat scattered, 
and some of them may represent centripetal xylem. The phloem dies out 
before the xylem, as it ordinarily does in the termination of the vascular 
bundles of the leaves. A small resin canal, which appears to be non¬ 
functional, accompanies the single vascular bundle in its passage from the 
cone axis, but this canal dies out very quickly. In Saxegothaea , on the 
other hand, the resin canal of the sporophyll is a much more conspicuous 
structure, and passes out practically as far as the xylem elements extend. 
The microsporangia of our material were either ready for dehiscence 
or else dehiscence had already taken place. Remains of two layers of cells 
within the sporangium wall could be made out. The wall of the sporangium 
is very much like that of Saxegothaea (10,17) and Araucaria (16). It is one 
cell wide except on the outside, and the vertical cell-walls are very thick, 
and have numerous strengthening bands on them running at right angles 
to the surface (cf. PI. XXI, Fig. i). The line of dehiscence of the 
sporangium is oblique, as can be seen by an examination of PI. XXI, 
Fig. 2 . Pilger (13) states that the dehiscence of the sporangium in the 
Taxaceae is longitudinal, but this is without doubt incorrect for P. spinu- 
tosus. Thibout (20) correctly figures the dehiscence of the microsporangia 
of several species of Podocarpus as being oblique. In Saxegothaea (17) 
the line of dehiscence is transverse. 
(2) Pollen-grains. 
As is well known, the pollen-grains of Podocarpus are winged like 
those of Pinus. The material of P. spinulosus available contained only 
pollen-grains which were mature. The material had been fixed in a dilute 
solution of formalin, and apparently had all been collected at one time. 
Several observers have recently related the occurrence of as many as eight 
prothallial cells in the pollen-grains of different species of Podocaipiis. 
Thibout (20) describes the presence of several prothallial cells in P. poly - 
stachyus. Coker (5) mentions the division in P. coriacea of the two original 
prothallial cells, but he considers that these divisions are abnormal. 
