196 



MOSSES AND FERNS 



CHAP. 



to find a somewhat similar state of affairs, so that the embryo 

 may be said to have two growing points, although the lower 

 end shows neither such regular nor so active growth as the 

 upper one. In the latter the divisions follow each other with 

 almost mathematical precision. There seems to be no rule as 

 to how many segments are cut off from the apical cell before 

 it ceases to function as such, but it is very much larger than 

 in Andrecea, and the embryo soon becomes extremely elongated. 

 A series of transverse sections of the young sporogonium shows 

 very beautifully the succession of the first walls in the young 

 segments. In a section just below the apex (Fig. 95, A), each 



Fig. 95. — Five transverse sections of a j'oung embryo of F. hygrometrica. A, Just below the apex, 

 the others successively lower down ; en, endothecium, X450. 



segment is seen to be first divided by a median wall into two 

 equal cells. In Funaria usually the next division wall is 

 periclinal, and at once separates endothecium and amphithecium. 

 In most other Bryineae that have been examined, however, 

 and this may also occur in FunaiHa (see Fig. 95, A), the 

 second walls formed in the young segments are anticlinal, and 

 it is not until the third set of walls is formed that the separation 

 of endothecium and amphithecium is complete. The next 

 divisions (Fig. 95, C) are in the amphithecium, and separate 

 it into two layers. In the endothecium now a series of walls 

 is formed, almost exactly repeating the first divisions in the 

 original segment (Figs. D, E), and transforming it into a group 



