WALTER P. THOMPSON 
Fig. 15. G. sp. 33. Mature ovulate flower, pe., perianth; st., style; cav., 
cavity in style; o.i., outer integument; id,, inner integument; n., nucellus; s., 
embryo-sac. X 50. 
Fig. 16. Peperomia sp. Young ovulate flower, ca., carpel. X 50. 
Plate III 
Fig. 17. G. sp. 33. Longitudinal section of style, n., nutritive layer; p., 
pollen grains; p.t., pollen tube. X 300. 
Fig. 18. G. sp. 33. Style. Later stage. Lettering as before. Shows dis- 
integration of nutritive layer. X 320. 
Fig. 19. G.sp.33. Young megasporangium. epidermis; a., archegonium. 
X 550. 
Fig. 20. G. sp. 33. Young megasporangium. p., parietal cells; m., mother 
cells. X 550- 
Fig. 21. G. sp. 33. Young megasporangium. Later stage showing one parietal 
cell divided. X 550. 
Fig. 22. G. sp. 33. Young megasporangium. Transverse section. X 550. 
Fig. 23. G. sp. 33. Young megasporangium, showing two mother cells, one of 
which is dividing. X 550. 
Fig. 24. G. sp. 33. Young megasporangium, showing one mother cell un- 
divided and two which have divided and produced daughter cells {d). X 550. 
Fig. 25. G. sp. 33. Megaspores and four-nucleate sac. X 550. 
Fig. 26. G. gnemon. Longitudinal section of young abortive ovulate flower 
from staminate strobilus. pe., perianth; n., nucellus; i.i., inner integument; o.i., 
rudimentary outer integument; s., embryo-sac. X 200. 
Fig. 27. G. gnemon. Transverse section of abortive ovulate flower, v.h., 
vascular bundles. X 50. 
Fig. 28. G. gnemon. Young microspore. X 1200, 
Fig. 29. G. gnemon. Microspore, t., tube nucleus; g., generative cell. 
X 1200. 
Fig. 30. G. gnemon. Microspore. Pollination stage. tube nucleus; h., 
body; stalk cell. X 1200. 
Fig. 31. G. g?iemon. Microspore. Stalk and generative nuclei in a common 
cytoplasm. X 1200. 
Fig. 32. G. sp. 33. Germinated microspore. X 550. 
Fig. 33. G. sp. 33. Pollen tube entering nucellus. b., body cell; t., tube 
nucleus; n., nucellus. X 550. 
Fig. 34. G. sp. 33. End of pollen tube, m., male nuclei; t., tube nucleus. 
X 800. 
Fig. 35. G. sp. 33. G. sp. 33. Tip of nucellus with pollen grains and tubes. 
St., stalk nucleus; p.t., pollen tube; n., nucellus. X 300. 
Plate IV 
Fig. 36. G. gnemon. Young embryo-sac. X 430. 
Fig. 37. G. gnemon. Two young embryo-sacs from same nucellus. X 430. 
Fig. 38. G. gnemon. Nearly mature embryo-sac showing mass of protoplasm 
and nuclei im.) at bottom. X 200. 
