VI MOSSES {MUSCJ): SFHAGNACEJ£— ANDRE /EACEAi 167 



branches, with which he regards them as homologous, having 

 observed in some cases a bud occupying the place of an 

 antheridium. He studied in detail their development, which 

 differs considerably from that of the other Mosses. The 

 antheridium arises from a single cell whose position corresponds 

 to that of a lateral bud on an ordinary branch. This cell 

 grows out into a papilla and becomes cut off by a transverse 

 wall. The outer cell continues to elongate without any 

 noticeable increase in diameter, and a series of segments are 

 cut off from the terminal cell by walls parallel to its base, so 

 that the young antheridium consists of simply a row of cells, 

 comparable to the very young antheridium of the Marchanti- 

 aceae. Intercalary transverse divisions may also arise, and 

 later some or all of the cells, except the terminal one, divide 

 by longitudinal walls, usually two intersecting ones in each cell, 

 so that the antheridium rudiment at this stage is composed of 

 a long stalk composed of several rows of cells, usually four, 

 and a terminal cell which later gives rise to the body of 

 the antheridium. The first divisions in the body of the 

 antheridium only take place after the stalk has become many 

 times longer than the terminal cell, and is divided into many 

 cells. ' 



The account of the development of the antheridium given by 

 Hofmeister and Schimper is incomplete, and differs in some 

 respects from that of Leitgeb. Neither of the former observers 

 seems to have clearly recognised the presence of a definite 

 apical cell from the first. Schimper ^ states that after the 

 stalk has been formed four rows of segments arise from the 

 terminal cell ; to judge from the somewhat vague statements of 

 Hofmeister - it appears that he regarded the terminal growth 

 as taking place by the activity of a two-sided apical cell, as in 

 other Mosses. Leitgeb states that, while this form of growth 

 does frequently occur, usually the divergence of the seg- 

 ments is not exactly half, and the segments do not stand in 

 two straight rows, but some of them are intercalated be- 

 tween these, forming an imperfect third row. Each segment 

 is first divided by a radial wall into nearly equal parts, and 

 these are then divided into an outer and an inner cell, and from 

 the latter by repeated divisions the sperm cells are formed. 

 The body of the full-grown antheridium is broadly oval, and 



, ^ Schimper (i), p. 45. " Hofmeister (i), p. 154. 



