472 
Stiles . — The Podocctrpeae. 
supply. These canals form roughly two rings concentric with the micropyle 
and nucellus (Text-figs. 4, d-f). 
The vascular supply of the ovule in P. macrophyllus is very similar to 
that of P. spinulosusp the chief difference being in the much greater distance 
the bundles descend towards the micropyle in P. macrophyllus . 
The vascular supply of the ovulate structure of P. latifolius is simpler 
than that of P. macrophyllus. The sporophyll bundle is accompanied by 
a great deal of transfusion tissue, and in the upper part of its course consists 
entirely of transfusion elements (PI. XLVII, Fig. 23). The ovular supply at 
the base of the stalk consists of two bundles as in other species, but these 
bundles do not divide further until the chalaza is reached (Text-fig. 5, a-c). 
Here each bundle divides into two, and the outer ones bend round through 
about a right angle and descend a very short way towards the micropyle 
(Text-figs. 5, c and d). The inner bundles proceed further towards the top 
of the ovule, where they ultimately meet and end in a mass of transfusion 
tracheides. A small bundle descends from this mass a short way (Text-fig. 
5, e), but does not reach the level at which the ascending bundles fork. As 
in P. macrophyllus, there is here a large development of canals concentric 
with the micropyle and nucellus, but two distinct rings cannot always be 
made out. 
It is clear that there is a good deal of variation in the vascular structure 
of the ovule throughout the section Eupodocarpus , and probably an exami- 
nation of a large number of cases would reveal the presence of a certain 
amount of variation among the individuals of one species. The essential 
facts seem clear ; the ovular supply consists of two bundles with inverse 
orientation as regards the sporophyll bundle. These two bundles sometimes 
divide between the base of the ovular stalk and chalaza, and nearly always 
in the region of the latter, into a more or less complicated system. This 
division has probably arisen owing to the needs of a well-developed conduct- 
ing system for the development of the large ovules and seeds. It has already 
been suggested that the same cause is responsible for the complete inde- 
pendence of the vascular supply of the ovule from that of the sporophyll. 2 
Having regard to the state of affairs in Dacrydium cupressinum, where 
the ovule is actually borne on the epimatium, I feel disposed to consider 
the ovular stalk as a further development of that structure. In Podocarpus, 
therefore, the ovule has been carried up a long way on to the epimatium, but 
the latter is almost completely fused with the integument, a point in which 
it differs markedly from Dacrydium cupressinum. 
The vascular system of the ovule of Podocarpus is therefore to be re- 
garded as a further development from that of the more primitive Podocar- 
peae. In a previous paper Mr. Brooks and the writer 3 stated that there was 
1 Brooks and Stiles (’ 10 ), PI. XXI, Figs. 15-18. 2 1 . c., p. 314. 
3 1. c., p. 315. 
