THE HIGHER CRYPTOGAM I A. 33 



to some extent (to the height of five cells), towards the 

 apex of the archegonium, the lower part of which thus 

 becomes enlarged. In the mean time, the horizontal 

 septa which divide the cells of the central string of 

 the archeo-oniimi from one another become dissolved 

 (PL Y, fig. 5). A canal, filled with mucilage, and closed 

 above, thus originates in the longitudinal axis of the archego- 

 nium. The cells which form the arch over its upper end sud- 

 denly part from one another, bending themselves somewhat 

 backwards ; an open passage, not obstructed by any cell- 

 wall, now leads from the outside through the entire length 

 of the archegonium down to the large cell in its swollen 

 lower part (PL V, figs. 6, 7). In the mean time there is 

 formed in the large cell a free spherical cell, enclosing 

 a central nucleus, and which, when fully grown, almost 

 fills the cavity of its mother-cell (PL V, figs. 6, 7). 



During the development of the first archegonia a thin 

 lamella of cellular tissue grows out of the upper surface of 

 the flat stem, from the point of insertion of the archegonia 

 backwards. It follows the longitudinal growth of the 

 archegonia, inasmuch as the cells of its fore edge con- 

 tinually divide by transverse septa, and its side edges unite 

 with the thin prolongation of the shoot which extends 

 itself underneath (in front of) the archegonium (PL V, 

 fig. 2). A pouch-shaped covering thus originates, which 

 is open in the fore part, and encloses the archegonium. It 

 entirely corresponds in its whole development with the 

 perianth of the leafy Jungermannise, especially in the fact 

 that it appears at a later period than the first rudiments of 

 the archegonia. Pellia must not be classed with the 

 Gyromitrise. 



The above condition is attained by all those archegonia 

 whose longitudinal growth is terminated before the time 

 when the rudiments of the fruit begin to appear in one of 

 the archegonia enclosed in the same perianth with them- 

 selves. The time of the development of the archegonia 

 is very uncertain : the earliest open at the beginning of 

 May ; the latest in the middle of July. Even then, those 

 flowers which contain no rudiments of fruit exhibit abortive 

 archegonia, in which the walls of the canal of the neck and 

 the wall and contents of the large cell in the expanded 



3 



