332 MOSSES 



planes of the apical cell. Each segment (c and G, seg. c] 

 immediately after its separation divides and subdivides, pro- 

 ducing a mass of cells from which a projection grows out 

 forming a leaf, and in this way the stem increases in length 

 and the leaves in number. 



Asexual reproduction takes place in various ways : all of 

 them are, however, varieties of budding, and the buds always 

 arise in the form of a linear aggregate of cells called a 

 protonema : from this the moss-plant develops in the same 

 way as from the protonema arising from a spore (p. 335). 



The gonads are developed at the extremity of the main 

 stem or of one of its branches, and are enclosed in a tuft of 

 leaves often of a reddish colour the terminal bud of the 

 fertile shoot or so-called " flower " of the moss. 



The spermary (Fig. 82, A 1 , A 2 ) is an elongated club-shaped 

 body consisting of a solid mass of cells, the outermost of 

 which form the wall of the organ, while the inner (A S ) become 

 converted into sperms. The latter (A 4 ) are spirally coiled 

 and provided with two cilia : they are liberated by the 

 rupture of the wall of the spermary at its distal end (A 2 ). 



The ovaries 1 (see Preface, p. x, and p. 377) (B 1 , B 2 ) may 

 or may not occur on the same plant as the spermaries, some 

 mosses being monoecious, others dioecious. Like the sperm- 

 aries they consist at first of a solid mass of cells which 

 assumes the form of a flask, having a rounded basal portion 

 or venter (v) and a long neck (n). The outer layer of cells 

 in the neck and the two outer layers in the venter form the 

 wall of the ovary, the internal cells are arranged in a single 

 axial row at first similar to those of the wall. As the ovary 

 develops the proximal or lowermost cell of the axial row 



1 The ovary of mosses, ferns, &c., is usually called an archegonium : 

 the spermary, as in the lower plants, an antheridium. 



