474 
Stiles . — The Podocarpeae. 
not sufficient data to decide to what extent the ovular supply in Podocarpus 
was to be homologized with that of other Gymnosperms. 1 If the origin of 
the ovular vascular system of Podocarpus suggested above is correct, it is 
obvious that the presence of a well-developed vascular system in the ovules 
of that genus is to be regarded as a fresh development, and is not 
homologous with that in any older Gymnosperms. 
ii. Nageia. In Podocarpus nagi the fertile branches arise in the axils 
of ordinary foliage leaves (PI. XLVII, Fig. 24). Each branch is about 1*5 cm. 
long and bears about six pairs of decussately arranged scales ; one of the 
uppermost pair bears the solitary ovule. The stalk is short as compared 
with this structure in some species of Eupodocarpus , and is fused at its base 
with the megasporophyll. The general appearance is that of an ovule termi- 
nating the shoot (PI. XLVII, Fig. 24). The ovule is large compared with 
that of P .macrophyllus ; thus ovules collected on July 13, when wall forma- 
tion had just commenced in the prothallus, were a centimetre long. At this 
time they are somewhat pear-shaped, the greatest transverse diameter being 
towards the upper or chalazal end of the ovule. Later, as the ovule becomes 
the seed, the latter becomes more spherical in shape (Fig. 24), and in material 
collected on October 5, which contained embryos with well differentiated 
cotyledons and radicle, the seed is a sphere about 1*5 cm. in diameter. 
As in other species, there are two integuments which are only free from 
one another for an extremely short distance at the micropylar end. Owing 
to the extent to which fusion of parts has taken place, it is not possible to 
define the limits of stalk and epimatium. In all the ovules I have seen 
there is on the side of the ovule remote from the stalk, and about three 
times as far from the micropylar end as from the chalazal end, a small 
projecting point which suggests the termination of a leaf or scale. 
Occasionally, there is more than one such point, as in the case figured in 
PI. XLVII, Fig. 24. There is, however, nothing in the internal structure to 
suggest a meaning for this, nor is there any suggestion of a difference 
between the tissues of the stalk and epimatium ; in the youngest stage 
examined the tissues of epimatium and stalk are quite similar : this is at 
about the time of wall formation in the prothallus. The integument and 
epimatium are at this time quite differentiated from one another, the cells 
of the epimatium being thicker walled with smaller nuclei, while the integu- 
ment consists of smaller thinner walled cells with relatively larger nuclei. 
In the epimatium are numerous canals, as in the species of Eupodocarpus 
examined ; these occur in all parts of the epimatium, but are most numerous 
around its inner limit (Text-fig. 6). 
As the ovule develops into the seed both integuments become 
differentiated into two layers, so that microscopically four layers can be 
recognized in the seed-coat ; a naked-eye examination, however, only 
1 Oliver (’03); Stopes (’04) ; Arber, A. (’10) ; Oliver and Salisbury (’ll). 
