462 EXPLANATION OF THE FIGURES. 



FIG. 



7. Longitudinal section of a very young fruit, whose apophysis is far larger 



than the capsule, x 60. 



8. A portion of the layer of mother-cells and of the adjoining tissue of a simi- 



lar fruit cut through longitudinally, X 300. 



9. A similar preparation from a somewhat more developed theca. The con- 



tents of the primary mother-cells of the spores and of the adjoining 

 cells of the columella are also shown. The primordial utricles of the 

 latter have contracted by lying in water. X 300. 



10. A similar preparation from a more advanced capsule, x 300. Here the 



nuclei of the cells immediately adjoining the layer of spore-mother- 

 cells, i. e., of the so-called inner capsule-wall, and the arrangement of 

 the chlorophyll of the outermost cells of the same are shown. The 

 chlorophyll in these cells lies closely attached to the free outer wall. 



11. Similar preparation from a capsule in which the formation of the spore- 



mother-cells within the primary mother-cells is just about to take 

 place, x 300. 



12. 12*. Spore-mother-cells with the enveloping primary mother-cells, x 300. 

 13 — 21. Stages of development of the spore-mother-cell, x 600. 



13. Young spore-mother-cell with central nucleus and homogeneous granular 



mucilaginous fluid contents. 



14. The nucleus is pushed near to the wall ; the protoplasm is accumulated 



chiefly in the middle point of the cell. 



15. This accumulation has divided into two halves. 



16. A secondary nucleus appears in each of them. 



17. 18. Four tertiary nuclei are seen in the place of the two secondary nuclei. 



19. The primary nucleus of the mother-cell has disappeared. 



20, 21. Spores fully formed. 



PLATE XXIII. 

 Figs. 1 — 11. Archidium phascoides. 



1. Archegonium ready for impregnation, X 250. 



2. Archegonium just impregnated, x 400. 



3. Fruit with two archegonia which have been some time impregnated, in 



longitudinal section, x 200. 



4. A young calyptra just ruptured by the swelling fruit, opened laterally, 



X 300. 



5. Young fruit cut through longitudinally and detached, x 200. 



6. The same somewhat more developed. The primary mother-cell of the 



spores has fallen out, x 200. 



7. The same, with the full number of cells. In the interior is a primary 



mother-cell enclosing four mother-cells. The contents of the latter are 

 omitted in the drawing, x 300. 



8. Primary mother-cell, with four mother-cells. The contents of the special 



mother-cells have contracted. 



9. Mother-cell with four lately formed spores, x 300. 



