EXPLANATION OF THE FIGURES. 455 



PLATE XIV. 



EIELLA REUTEKI. — Mont. 

 FIG. 



1 and 2. Germ-plants with spore attached, x 150. 



3. A plant produced by the multiplication of a cell of a leaf separated mecha- 



nically from an older individual, x 130. 



4. Adventitious shoot of an older plant, x 150. 



5. Full-grown shoots (cultivated, more slender than in the natural state) ; 



the older part of the plant is dead, x 5. 



6. Another similar shoot, x 20. 



7°. The end of the shoot a of the latter, x 200. 



8. Terminal bud of a strong shoot after the removal of the older leaves, 



X 200. The leaves and the upper layer of cells of the massive portion 

 of the stem — which latter, as far as the drawing extends, consists of only 

 two layers of cells — are shown in dark lines above the outlines of the 

 membranous wing and the second cellular layer of the stem. 



9. Longitudinal section of a terminal bud perpendicular to the surface of the 



stem, x 200. 



10. Terminal bud after the removal of all leaves. Two antheridia are being 

 formed, the one sunk half down, the other deep down into the duplica- 

 tions of the margin of the wing, x 150. 



10. Young unicellular antheridium with adjoining tissue, laid bare by a sec- 

 tion parallel to the surface of the wing of the stem, x 150. 



12. Longitudinal section of a half-ripe antheridium, X 150. 



13. Section through a portion of a fertile shoot which has laid bare an arche- 



gonium recently impregnated, and has grazed a lateral axis bearing 



antheridia, x 100. 

 14°. Unimpregnated archegonium with its apex still closed, X 250. 

 14*. Archegonium ready for impregnation, X 250. 



15. Longitudinal section of a recently impregnated archegonium, x 250. 



16. Young calyptra just visible through its veil, X 25. 



17. Longitudinal section of a calyptra with sporangium (a younger state than 



Fig. 16), x 200. 



18. Longitudinal section of the same when half ripe, the section not having 



passed through the mouth, X 100. 

 19°, Mother-cell with four spores enclosed in special-mother-cells, X 250. 

 19*. Rudimentary elater from the same sporangium, X 250. 



PLATE XV. 



Pigs. 1 — 18. Marchantia polgmorpha. 



1. Longitudinal section perpendicular to the surface of a shoot bearing a very 



young bud-receptacle, X 50. 

 1*. The bud-receptacle of the last figure cut through, X 200. 



2. Young bud, x 400. 



