Female Strohilns in Podocarpus . 571 
Fig. 68. Strobilus with three bracts, two of which are fertile ; macrospore stage with dividing 
nuclei, x 8. 
Fig. 69. Strobilus with three bracts, one of which is fertile ; the lamina of the bracts are reduced 
to points, while the bases are much swollen and of a bright red colour ; young embryo stage, x 8, 
red. f. 
Fig. 70. Strobilus with two bracts, both unmodified ; ovule in young embryo stage, x 8, red. |. 
Fig. 71. Strobilus with three bracts ; the lamina of one bract with an undeveloped ovule is dead, 
x 8, red. 
PLATE LIII. 
Sections cut 2-3 /x on a Minot microtome. 
Fig. 72. P. vitiensis. Transverse section through an ovule in the pollination stage, taken below 
the base of the nucellus, where the four bundles of the scale break up into branches which run down 
the lamina of the same (Fig. 17). In this case eight branches can be counted ; the integument shows 
a thick ring of tannin and starch cells, the walls of which are becoming lignified. This ring is seen 
penetrated in two places by phloem strands from the vascular system (Fig. 17). The tannin cells 
surrounding the base of the nucellus are seen in the integument, which is limited by an epidermal 
layer of tannin cells. Similar cells mark the peripheral layer of the nucellus, which is bounded on 
the inside by the tapetum in which lies the dividing macrospore, x 24. 
Fig. 73 * Transverse section, same series, taken through the micropyle and the base of the ovuli- 
ferous scale, just above the apex of the nucellus where the four bundles have again approximated, 
x 25. 
Fig. 74. P. spicata. Longitudinal section of nucellus only, showing the well-marked tapetum, 
megaspore membrane, and free cell formation in the prothallus. x 1 20. 
Fig. 75. Longitudinal section of ovule, showing zone of stone cells (torn) in the ovuliferous 
scale, with the zone of tannin and starch cells lining the integument and the nucellus. The cells at 
the apex of the nucellus contain starch and show some pollen-tubes ; on the inside the nucellus is 
limited by the tapetum. The prothallus is very much contracted, but the megaspore membrane can 
be traced folding in and out with the prothallial tissue, which shows cell-wall formation, x 45. 
Fig. 76. P. ferruginea , longitudinal section of young strobilus in the stage of Fig. 25. 
It shows an undifferentiated nucellus with basal cell growth and a limiting layer of tannin cells to 
the nucellus and the free portion of the integument ; in the ovuliferous scale the tannin cells at this 
stage are limited to the epidermis and two or three hypodermal layers, x 27. 
Fig. 77. Transverse section through the nucellus, integument, and bract bases of the same stage. 
The two vascular bundles are seen with the xylems converging, whereas in the apex of the scale the 
phloems face each other. This rotation finally leads to a normal orientation as the bundle slips into 
its place in the ring of leaf- traces in the strobilus. x 42. 
Fig. 78. P. neriifolia. Longitudinal section of strobilus in pollination stage (Fig. 49), showing 
a very attenuated ovuliferous scale ; a well-marked tapetum is seen in the nucellus, enclosing the 
enlarging megaspore, x 7. 
Fig. 79. P. elata. Longitudinal section of strobilus with undifferentiated nucellus (Fig. 31), 
showing modified bracts with swollen bases, proliferation of mesophyll tissue ; also the independence 
of the vascular system of the fertile scale and the sterile bract at the base of the strobilus, indicated 
by the two resin canals far apart, x 26. 
Fig. 80. Transverse section of strobilus in above stage, taken at the apex of the nucellus, showing 
lamina of the fertile bract. Slightly oblique, x 40. 
Fig. 81. P. nivalis. Transverse section: of an ovuliferous scale taken across the micropyle, showing 
the foliar structure of the scale, x 45. 
