569 
Female Strobilus in Podocarpus. 
Fig. 29. Longitudinal section of strobilus slightly older than above stage; phloem strands pene- 
trate to the nucellus from the vascular bundles ; the tannin cells of the integument show a symmetrical, 
laterally elongated arrangement ; pollen-tubes have penetrated half-way down the apex of the nucellus, 
and the very contracted prothallus shows cell-wall formation ; a scar is all that remains of the 
lamina of the fertile bract ; in section the arrangement of the bracts in the strobilus is seen to be 
more spiral than opposite and decussate, as the morphology would suggest, x 8, red. |. 
Fig. 30. P. elata. Earliest stage, showing strobilus of four bracts, the lower pair being narrower 
than the upper, of which one is fertile ; all four enclose the ovuliferous scale. Ventral view, the 
opposite sterile bract having been removed, x 16. 
Fig. 30 a. Dorsal view of fertile bract, showing unmodified lamina and base, x 16. 
Fig* 3 1 - Older stage, ovuliferous scale showing above the bracts, which are becoming broader 
and thicker, x 16. 
Fig. 31 a. Lateral view, showing both upper bracts, with the lower pair dissected off. x 16. 
Fig. 31 b. Ventral view of same, showing micropyle. x 16. 
Fig. 32. Strobilus showing lower bracts which remain undifferentiated ; the upper pair show 
shrinking laminae and swollen bases. Pollination stage, x 16. 
Fig. 32 a . Ventral view of above, showing sterile bract cut off, to expose micropyle. x 16. 
Fig- 33- Strobilus with ovule showing young embryo ; the unmodified bracts still persist, the 
upper bracts show very swollen bases and laminae shrunk to points ; the ovuliferous scale extends 
above the fertile bract, x 16, red. f. 
Fig. 34. Group of tracheides terminating a vascular bundle in the lamina of the ovuliferous 
scale, x 625. 
Fig- 35- P. polystachyci. Strobilus with ovule, showing embryo ; the unmodified lower bracts 
have been shed and in the upper ones all foliar structure is lost, the lamina being no longer indicated, 
While the bases are fused in a succulent whole. Nat. size. 
Fig. 36. Longitudinal section of prothallus, showing complex of proembryos, one being formed 
from each archegonium ; the suspensor bearing successful embryo is seen penetrating the central 
cylinder of prothallus, the cells of which are binucleate, and those immediately below the embryo 
show dense starch contents, x 245. 
Fig* 37 * Longitudinal section of prothallus, showing embryo increasing in size at the expense 
of the central cylinder ; the remains of the suspensor tubes are still traceable, also the cavity formed 
by proembryos, with disorganized remains of complex ; contraction of tissue is shown at the apex 
of the prothallus, causing the epidermal layer to fold in and out. x 16. 
PLATE LI. 
Fig. 38. Longitudinal section of ovule enclosed in the ovuliferous scale, showing stone cells 
scattered in the mesophyll of the latter, also laminal branching of the vascular bundles; the integu- 
ment shows lignification of the cell-walls and the nucellus is reduced to the apex, which, still showing 
starch and pollen-tube, forms a mere cap ; the prothallus has grown at the expense of the nucellar 
tissue, and shows an undifferentiated embryo ; the cavity left by the complex of proembryos has almost 
closed, though still filled with the crushed remains ; digested cells surround the embryo, and the crushed 
and empty tissue of the cells of the central cylinder is being pushed down as a plug by the vertical 
growth of the embryo, x 16, red. |. 
Fig. 39. Longitudinal section of embryo, showing differentiation of the cotyledons, root apex, 
and resin canals ; the dotted area shows the relative distribution of starch in the prothallus, of which 
the cells, excluding the peripheral layer, are multinucleate. x 8, red. f . 
Fig. 39 a. Multinucleate cells of the prothallus, packed with starch grains, x 625. 
Fig. 39 b. Peripheral layer of the prothallus, with megaspore membrane, x 625. 
Fig. 40. Nucleus in prothallial cells, on initiation of division, showing four daughter nuclei 
still enclosed in the limiting membrane, as seen in Fig. 36, in the cells of the central cylinder, just 
below embryo. (L. Digby del.) 
Fig. 41. Sterile strobilus borne on same tree as the fertile one drawn in Fig. 35. Nat. size. 
Fig. 42. Longitudinal section of above. In this prothallus, which contains no starch, tracheides 
are developed in the central cylinder ; a cavity occurs where the archegonia would normally be found- 
x 16. 
