THE HIGHER CRYPTOGAMIA. 3 



is much interrupted by the fact that individual marginal 

 cells, and in Anthoceros punctatus even the surface cells, 

 become transformed into adventitious shoots. The circum- 

 stances under which the plant grows have a decided in- 

 fluence upon the number of the adventitious shoots which 

 come to perfection ; and these circumstances also determine 

 whether the growth of such shoots shall terminate at an 

 early period, or whether, like the mother-shoots, they shall 

 continue to ramify and develope themselves. The latter is 

 always the rule in Anthoceros punctatus. It contributes 

 much more to the crisped, distorted aspect of the plants of 

 this species, than the perishing of the upper coverings of 

 the air-cavities which are enclosed in their tissue. In 

 Anthoceros lavis, ramification only takes place when the 

 plant grows in a very moist atmosphere and in deep shade. 

 Then A. Icevis ramifies to as great an extent as the other 

 species, from which, however, it is decidedly distinguishable 

 by the entire absence of air-cavities in its tissue. 



The flat stem of Anthoceros grows and elongates itself 

 by continual division of the cells of its fore edge. These 

 cells have the form of a three-sided prism, with one side 

 (that, viz., which forms the fore edge) convex. These cells 

 divide repeatedly by septa, which are inclined at angles of 

 about 45° alternately towards the upper and under surfaces 

 of the flat stem. In the cell constituting the fore edge 

 (viz., the cell of the first degree), the division is repeated 

 until the full number of cells belonging to the segment 

 (which segment is limited in its longitudinal growth) is 

 reached. This cell-multiplication terminates at a later 

 period in the median line of the segment than it does at 

 the sides. Hence it follows, that the shape assumed by 

 each of the three lobes of the fore edge of a shoot is that 

 of the segment of a circle. The cells of the second degree, 

 which are distinct from the three-sided prismatic cells of 

 the fore edge, have the form of procumbent prisms with 

 a rhombic base. Each newly formed cell of the second 

 degree divides immediately by a septum parallel to the free 

 outer surface. This division is followed by that of the 

 inner and outer daughter-cells, which takes place by means 

 of a septum parallel to the neighbouring cell, and at right 



