MOSSES AND FERNS 



CHAP. 



the antheridium ripens, these gradually assume a bright orange- 

 red colour. The development of the stalk varies in different 

 cases. Sometimes it consists of a row of several cells, some- 

 times the antheridium is almost sessile. The lowermost seg- 



FIG. 103. Funaria hygrometrica. A, Antheridium that has just discharged the mass 

 of sperm cells (B), X3oo; C, spermatozoids, Xi3oo; D, paraphysis, X3oo; E, 

 male "flower" of Atrichum undulatum, X6. 



ments of the apical cell help to form the upper part of the 

 stalk, and sometimes the two lowest seem to take no part in the 

 formation of the sperm cells. There is no absolute uniformity 

 in the cell divisions of the stalk, which varies in the arrange- 



