THE HIGHER CRYPTOGAMIA. 437 



growth is caused by the repeated division by horizontal 

 septa, of four cells constituting the upper end of the fruit- 

 rudiment. But the normal mode of cell-multiplication in 

 the fruit-rudiment of the Marchantieae (including the 

 Targionieae), and of the Riccieae, coincides exactly with 

 that of the mosses. Lastly Anthoceros exhibits a form of 

 cell-multiplication of the endogonium which is the same 

 as that of the punctum vegetationis of the ends of the axes 

 of a great number (probably the majority) of phaenogams. 

 The septa produced in the one apical cell of the organ, are 

 inclined in regular succession towards the four points of 

 the compass. The presence or absence of a columella, or 

 of elaters in the ripe fruit, are points of no characteristic 

 value ; Anthoceros has the columella, but this genus and 

 the Riccieae have no elaters. Radula in the Jungerman- 

 nieae has a vao-irmla, and so has Anthoceros. 



Upon instituting a closer comparison between the mode 

 of development of different forms, four types soon become 

 conspicuous, around which all the phenomena hitherto 

 sufficiently investigated may be conveniently arranged. 

 We thus arrive at the following equivalent groups, which 

 are not however equally rich in the number of genera and 

 forms. 



1. Mosses according to the ordinary limits of the family, 

 including the Sphagnaceae. 



2. Jungermannieae ; in which the leafy ones are con- 

 nected with the leafless ones by a succession of inter- 

 mediate stages. 



3. Marchantieae, Targionieae and Riccieae; all intimately 

 connected with one another by the similarity of the earliest 

 conditions of the fruit, as well by many vegetative pheno- 

 mena.* 



4. Anthoceroteae. 



The mode in which the second generation originates 

 from, the first is much more various in the vascular crypto- 

 gams than in the others. All ferns however agree in the 



* As for instance the precisely similar succession of the shoots ; the separa- 

 tion of the tissue of the shoots into an upper layer with intercellular caviiies, 

 and a lower layer without cavities ; the occurrence of peculiar thickenings upon 

 the inner wall of the capillary roots, &c. 



