THE HIGHER CRYPTOGAM IA. G5 



fig. 1). They grow by continually repeated division of a 

 single apical cell by means of septa alternately inclined in 

 different directions. These shoots are also remarkable from 

 the fact that in the older portion of them each epidermal 

 cell grows out into a short papilla (PL VII, fig. 2), an en- 

 largement of the upper surface, which may serve as a 

 compensation for the absent rootlets. 



The antheridia of the liverworts are mostly axile, some- 

 times solitary (Jungermannia, Lophocolea, Radula, Ma- 

 dotheca), sometimes gregarious (Alicularia, Prullania), in 

 the axil of the same leaf. They are only occasionally free, 

 i. e., not protected by covering leaves on the upper surface 

 of the stem (Fossombronia, Haplomitrium) . The formation 

 of the antheridium commences by the protrusion outwards 

 in the form of an arch, and to a considerable extent, of 

 one of the cells of the upper surface of the stem, before 

 the latter has ceased to grow in thickness, and by the sepa- 

 ration, by means of a transverse septum, of the protu- 

 berance thus formed from the original cell cavity. In the 

 cell thus formed, which protrudes above the surface of the 

 stem, there sometimes commences a series of repeated 

 divisions of the apical cell by septa alternately inclined in 

 two directions {Madotheoa platyphylla, Fossombronia pu- 

 silla). This series of divisions, however, is not of frequent 

 occurrence. More frequently the primary cell of the 

 antheridium is divided several times successively by septa 

 parallel to one another. By this means it is transformed 

 into a row of cylindrical cells, which is sometimes of con- 

 siderable length, as in Lophocolea heteropltylla. The ter- 

 minal cell of this cellular thread swells in a clavate manner 

 (PL XI, fig. 39). It divides by a septum diverging from 

 its longitudinal axis ; the upper one of the newly formed 

 cells then divides by a septum inclined in the opposite 

 direction. The cells of the second degree are divided by 

 radial longitudinal septa ; one of the cells of that upper 

 pair of cells of the third degree which is nearer the apex of 

 the antheridium, divides by a septum parallel to the longi- 

 tudinal axis, and cutting the side walls of the mother-cell 

 at an angle of 45. The young antheridium now consists 

 of a spherical group of cells a central cell surrounded by 



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