474 EXPLANATION OF THE FIGURES. 



FIG. 



2. Longitudinal section through the middle line of the frond destined for 



development in the following spring in the bud-region of a similar stem, 

 x 20. 

 2*. The terminal bud and the two youngest fronds of the latter specimen, 

 x 200. 



3. Transverse section close above the terminal bud of a similar stem, x 20. 

 3*. Transverse section through the same stem, i line lower down. 



4. Transverse section close above the terminal bud, which is seen through the 



opening of the narrow canal leading to it, x 300. 



Pigs. 5 11. Botri/chium Lunaria. 



5. Longitudinal section of a prothallium, X 50. Above, to the right, is an 



archegonium ; on the left of this are five autheridia, of which three are 



empty. 

 G. Longitudinal section of autheridia shortly before opening, X 300. 

 7. Hinder end of a prothallium, with remains of the spore-membrane, X 300. 

 8 10. Germ-plants with adherent prothallia, x 6. Figs. 8 and 9 seen from 



the side, fig. 10 from above ; p, prothallium ; a, the end of the primary 



axis of the germ-plant. 

 10*. The germ-plant. Fig. 10, longitudinal section, with adherent prothallia; 



ff, the end of the bud of the principal axis of the germ-plant, x 30. 



PLATE XLII. 



1. Germ-plant with prothallium seen from above, X 6. 



1*. The same cut through longitudinally in the direction from a to p. 



2, 3. Abortive germ-plants whose prothallia are already dead, x 6. 



4, 5, 6. Normally developed germ-plants, about one year old. Natural size. 



7, 8. Germ-plants whose second frond already projects out of the lower first 

 frond, x 2. 



9. The same cut through longitudinally, X 20. The first frond has already 

 died down to a hardly perceptible membranous border. In the stipule- 

 like second frond the rudiments of the third and fourth lie concealed. 



10. A plant dug up in September, 1854, cut through parallel to the surface of 



the frond destined for development in the following spring. Natural 

 size. 

 10*. The lower part of this specimen, x 20. 



10". Terminal bud of this specimen, in a position turned from the right to the 

 left, x 300. 



11. Section of the bud of a plant in full growth at the beginning of June. The 



rudiment of the fertile frond is already visible close by the enclosed frond 

 destined for development in the next year but one. 



