PLATE 20 



Aplanes Treleaseanus 



Fig. I. Gemmae. X 503- 



Fig. 2. Proliferating sporangia. X 278. 



Fig. 3. Sporangia in basipetal arrangement. X 278. 



Fig. 4. Gemmae. X 278. 



Fig. 5. Oogonium with a single ripe egg. X 503. 



Fig. 6. Oogonia with large papillae. X 503. 



Fig. 7. Gemmae in basipetal arrangement. X 278 



Fig. 8. Empty oogonium (optical section and surface view combined). X 50.^- 



Fig. 9. Oogonium with a single papilla. X 503- 



Fig. 10. Irregularly shaped oogonium with ripe eggs. X 503. 



Figs. II, 12 and 13. Various forms of oogonia and antheridia. All X 503- 



