196 



MOSSES AND FERNS 



CHAP. 



Whether the first antheridium, as in Andrecea and Fontinalis, 

 arises from the apical cell is doubtful, and it is impossible to 

 trace any regularity in the order of formation of the very 

 numerous antheridia. Except in old plants, all stages of de- 

 velopment are found together, and the history of the anther- 

 idium may be easily followed. A superficial cell projects above 

 its neighbours, and this papilla is cut off by a transverse wall. 



H 



FIG. 102. Funaria hygrometrica. ' Development of the antheridium. A-D, Longitudinal 

 sections of young stages, X6oo; D is cut in a plane at right angles to C; E, optical 

 section of an older stage, X3oo; G, F, cross-sections of young antheridia, X6oo; 

 H, diagram showing the first divisions in the antheridium; I, young spermatozoids, 



XI200. 



The outer cell either becomes at once the mother cell of the 

 antheridium, or other transverse walls may occur, so that a 

 short pedicel is first formed (Fig. 102, A). Finally in the 

 terminal cell, as in Andreaa, two intersecting walls are formed 

 enclosing a two-sided apical cell, from which two ranks of seg- 

 ments are cut off in regular succession (Figs. A, B, C). The 

 number of these segments is limited, in Funaria not often ex- 

 ceeding seven, and after the full number has been formed, the 



