VI. 



THE BRYALES 203 



massive pedicel is formed, the apical cell divides, as in Fiinaria, 

 into an inner and an outer cell. The former, as usual, gives 

 rise to the central cell, from which later arise the egg and ven- 

 tral canal cell, and a second cell, which is the primary neck 

 canal cell. The latter, according to Holferty, undergoes fur- 

 ther divisions and the secondary canal cells, cut off from the 

 base of the apical cell, also undergo further divisions. There 

 may be as many as ten neck canal cells finally developed. 



Holferty also describes and figures several abnormal struc- 

 tures, intermediate in character between the archegonium and 

 antheridium. 



While in Fimaria and Polytrichiim the plants are regularly 

 dioecious, in many Mosses this is not the case. Both antheridia 

 and archegonia may occur in the same ''inflorescence," or they 

 may be in separate groups upon different parts of the same 

 plant. Some doubt has been thrown upon the nature of the so- 

 called hermaphrodite inflorescences, and it is possible that they 

 are really composed of distinct but closely approximated inflor- 

 escences. (Satter (2) ; see Ruhland (i), pp. 204, 205.) 



The Sporophyte 



The first (basal) wall in the fertilised ovum divides it into 

 an upper and lower cell, as in Sphagnum and Andrecua, and the 

 next divisions correspond closely to those in the latter. In both 

 cells a wall is formed intersecting the basal wall, but not at 

 right angles. This is especially the case in the upper cell, where 

 a second wall strikes the first one nearly at right angles, and 

 establishes the two-sided apical cell by wdiich the embryo grows 

 for a long time. In the low^er cell the divisions are somewhat 

 less regular, but here also it is not uncommon to find a some- 

 what similar state of affairs, so that the embryo may be said to 

 have two growing points, although the lower end shows neither 

 such regiflar nor so active growth as the upper one. In the lat- 

 ter the divisions follow each other w^ith 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 there are more than in Andrecoa, 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 sec- 

 tion just below the apex (Fig. 107, A), each segment is seen to 



