THE HIGHER CRYPTOGAMIA. 119 



place within this covering (PI. XV, fig. 21). At the same 

 time broad, fleshy, cellular masses, concave above and 

 within, rise out of the angles between the median shoot 

 (which bears the archegonia) and the lateral wings. They 

 amalgamate with one another, and by their upper margin 

 they unite with the above-mentioned covering. Thus, there 

 is formed a blunt, triangular envelope, enclosing the lower 

 part of the archegonia, from the narrow three-sided opening 

 of which the apices of the unimpregnated archegonia pro- 

 trude (PI. XV, fig. 21). The rather thin walls of the enve- 

 lope, which are turned downwards, consist of homogene- 

 ous cellular tissue. 



When a rudimentary fruit is formed in an archegonium 

 the envelope enlarges with wonderful rapidity, especially by 

 expansion of its cells. It very soon entirely encloses the 

 impregnated archegonium. The cells adjoining the mouth, 

 which continues very narrow, grow out into short papillae. 



The archegonia are slender, almost cylindrical. The 

 cropped appearance of the apex, which occurs also in the 

 archegonia of the Marchantieae, is seen with remarkable dis- 

 tinctness (Pl.XV,figs. 22,23). The cells of the ventral portion 

 double themselves at an early period by septa parallel to the 

 circumference. The inner cells adjoining the central cell be- 

 come filled with granular matter, as in Pellia (PL XV, fig. 

 22). Immediately after impregnation the cells of the incipient 

 calyptra multiply very rapidly, so that, as in Rebouillia, 

 the central cell becomes a fusiform cavity, in which the 

 mother-cell of the rudimentary fruit lies free (PL XV, 

 fig. 22). 



The rudimentary fruit in its earliest youth is narrowly 

 spindle-shaped, composed of two double rows of cells (PL 

 XV, fig. 24, detached; fig. 23, enclosed by the calyptra). The 

 growth in thickness begins much earlier at the upper end 

 than at the lower (PL XV, figs. 23, 25). The latter pene- 

 trates deeply into the tissue of that portion of the stem 

 which bears the impregnated archegonium, and which has 

 become transformed by active and repeated division of its cells 

 into a conical, cellular mass. The lower end of the rudi- 

 mentary fruit, which is originally of a pointed, conical form, 

 changes gradually into a spherical enlargement by trans- 



