454 EXPLANATION' OF THE FIGURES. 



PLATE XIII. 



riccia glatjca. 



tig. 



1. Germ-plant (from a shady habitat) to which the spore is still attached, 



x 200. 



2. Developed germ-plants from the same locality, X 20. 



3. Perfect shoot seen from below, x 8. 



4. A young shoot in the bud seen from above, X 30. 



4*. Fragment of a capillary root of the median line of a perfect shoot. The 

 inner wall is furnished with prominent points, x 200. 



5. Three-celled rudiment of antheridium not yet grown over by an annular 



wall, x 200. 



6. Rudiment of an antheridium and part of a longitudinal section of a very 



young shoot. The yet undivided mother-cell of the organ is already 

 grown over by an annular wall, x 300. 



7 a . Longitudinal section through the fissure of the fore-edge of a perfect 

 shoot. The upper part of the figure is the lateral surface — through 

 which the section has passed — of the deep indentation of the fore-edge ; 

 the shaded part is the cavity of the lower portion of the latter, in which 

 the median shoot is developed, x 30. 



7 b . Longitudinal section of the median shoot bearing two rudiments of anthe- 

 ridia, one is unicellular and the other is a few-celled oval body sur- 

 rounded by a wall closing over the apex of the organ, X 400. 



8. Longitudinal section of a half-developed antheridium, x 300. 



9. Similar section of an almost ripe antheridium, x 200. 



10. Mouth of the sheath of a ripe antheridium, seen from the outside, X 300. 



11. Longitudinal section of a young shoot bearing the rudiment of an arche- 



gonium, X 400. 



12. Section of a more developed rudiment of an archegonium, x 400. 



13. Section of an archegonium whose longitudinal growth is terminating, 



x 300. 

 11. Longitudinal section of a shoot bearing an archegonium ready for impreg- 

 nation, x 300. 



15. An abortive archegonium whose mouth has been laid open by a longitu- 



dinal section through the shoot, x 300. 



16. Section of an impregnated archegonium with a fruit-rudiment still unicel- 



lular. 

 16*. Lower part of a section of an archegonium lately impregnated with a three- 

 celled fruit-rudiment, X 200. 



17. 18. Longitudinal sections of an archegonium with more fully developed 



fruit-rudiments, x 300. 

 19. Longitudinal section of a young capsule enclosed by the calyptra, x 200. 



