568 Gibbs. — On the Development of the 
Fig. 8 c. Resin canal with epithelium of thin-walled cells with active nuclei and darker staining 
contents, surrounded by cells containing tannin and starch, x 625. 
Fig. 9. P. dacrydioides. Longitudinal section of pollination stage ; tannin and starch cells show 
at the base of the integument and nucellus, with starch in the apex of the latter, and a well-marked 
tapetum limiting on the inside ; megaspore shows dividing nuclei, x 16, red. \ 
Fig. 10. Peduncle with imbricating scale leaves, terminated by strobilus of three bracts, one 
fertile, the lamina of which is fused with the ovuliferous scale. x 8. 
Fig. 11. Strobilus showing two bracts, one fertile, older stage, x 8. 
Fig. 12. Strobilus of three bracts, one fertile, x 8. 
Fig. 13. Longitudinal section of above stage: the prothallus is contracted, but shows centri- 
petal filling by free nuclear division, x 16, red. |. 
Fig. 14. P. vitiensis , showing position and branching of peduncles, each branch bearing 
a strobilus with one fertile bract ; the ovules are in the fertilization stage, the upper ones on simple 
peduncles being younger. Nat. size. 
Fig. 15. Young strobilus, showing peduncle with imbricating scale leaves; the strobilus is com- 
posed of five pairs of bracts, opposite and decussately arranged, with one of the upper pair fertile ; 
the lamina of the fertile bract is free from the ovuliferous scale, which bears an ovule with undifferen- 
tiated nucellus. x 16, red. 
Fig. 16. Peduncle with eight bracts, of which the upper two are fertile ; the ovuliferous scales 
bearing the ovules have grown far above the lamina of the fertile bracts ; these laminae, with those 
of the sterile bracts, subsequently desiccate and fall off, leaving only the elongated bract bases, as in 
the last species, which remain unmodified ; fertilization stage, x 16, red. f . 
PLATE L. 
Fig. 17. Longitudinal section of above stage, showing the growth of the lamina of the ovuli- 
ferous scale, that of the fertile bract remaining stationary ; the prothallus shows contraction, but 
archegonia are traceable in its tissue : <J prothallia show above the archegonia, the stage being just 
prior to fertilization, x 16, red. |. 
Fig. 18. Male prothallus with pollen-tube, which has penetrated the unusually long apex of the 
nucellus, showing two generative nuclei, with stalk and tube nucleus, x 245. 
Fig. 19. P. spicata. Bbranch showing strobili in the axils of the foliage leaves. Nat. size. 
Fig. 20. Strobilus bearing three fertile tracts, showing bud scales at base, and modified foliage 
leaves above, which are succeeded by the fertile bracts and an apical bud. x 16, red. 
Fig. 21. Strobilus of which the apical bud has been damaged, leaving only a cicatrized scar; 
this fact has probably stimulated the development of the modified leaves into foliage leaves ; one 
fertile tract on the shoot, x 16, red. |. 
Fig. 22. Longitudinal section of strobilus, showing produced apex of ovuliferous scale. A 
regular zone of stone cells occurring in groups of two or three is seen in the mesophyll ; phloem 
strands penetrate to the nucellus, and the vascular bundles send secondary branches into the lamina 
of the scale ; the prothallus shows contraction, but free cell-division can be traced, x 16, red. f. 
Fig. 22 a. Section through micropyle, showing non-septate closing cells, x 625. 
Fig. 23. Stone cells in the mesophyll of the ovuliferous scale, x 625. 
Fig. 24. P. ferruginea. Strobilus with peduncle in the axil of a foliage leaf ; the fertile bract 
slightly covers the ovuliferous scale ; pollination stage, x 8. 
Fig. 25. Strobilus in younger stage with scale leaves dissected off the peduncle; the bracts 
are still folded and protect the ovule enclosed in the scale; the nucellus is undifferentiated, x 16, 
red. f. 
Fig. 26. Strobilus and peduncle still enclosed in the scale leaves investing the latter, x 16, red. j. 
Fig. 27. Peduncle bearing strobilus composed of six pairs of bracts, of which one of the upper- 
most pair is fertile ; the ovuliferous scale shows above the bract ; scale leaves clothe the peduncle, 
x 16. 
Fig. 27 a. Ventral view of same, showing micropyle. x 16, red. j. 
Fig. 28. Strobilus with two fertile bracts ; ovuliferous scale has grown up above the bracts, of 
which only the bases persist, the laminae having shrunk to pin points; scars indicate the sterile 
bracts, of which the laminae have already been shed ; pre- fertilization stage, x 8, red. |. 
