THE HIGHER CRYPTOGAMIA. 29 



up apparently to the apex of the parent shoot through the 

 distortion of the outline of the latter, whilst the other 

 appears at some depth below, closely pressed to the side 

 (PL IV, figs. 20, 21). The former is always developed 

 more rapidly than the latter (PL IV, fig. 22), which often 

 fails altogether, often remains quiescent for months and 

 then suddenly begins to grow. Most of the disturbances of 

 the regular furcate ramification have their origin in the 

 circumstances just mentioned. 



It is only in barren plants (where it often occurs) that 

 shoots are found on the upper side also of the flat stem. 

 In individual cells of the surface there commences a pro- 

 cess of cell-multiplication differing, so far as regards its 

 regular mode of progression, in no material respects from 

 that which obtains in the germination of spores (PI. IV, 

 tig. 28). A number of shoots of the above nature, similar 

 to germ-plants, only more fleshy, are often situated close 

 together: in old joints of the stem I have counted as many 

 as thirty upon a single joint. The tufted mode of growth 

 of barren Pellige in flowing water may, perhaps, be owing 

 to these shoots. 



On the upper side of the earliest spring-shoots of fertile 

 Pellia?, club-shaped cellular masses are protruded, consist- 

 ing of a short central string, usually of only two cells, sur- 

 rounded by a single layer of four cells, each lying at the 

 same elevation (PL IV, fig. 29) : these are the first rudi- 

 ments of the antheridia. The arrangement of the cells leads 

 to the conclusion that they have originated in the division 

 by means of septa inclined alternately in different directions, 

 of one of the cells of the upper surface. Each cell of the 

 second order is divided by a longitudinal septum ; two of 

 the cells thus formed, which are placed one above another, 

 and have almost the form of the quadrant of a cylinder, are 

 divided by a septum cutting the side-walls at an angle of 

 45, into an inner three-sided and an outer four-sided 

 cell, of which the latter has an arched outer surface. This 

 determines the structure of the first rudiments of the 

 antheridium. By continual multiplication of the five cells 

 of its clavate end, the inner one of which divides in all 

 three directions, the four outer ones only in the direction 



