128 



STRUCTURAL BOTANY 



The leaves are arranged in a spiral, with a divergence 

 of |, that is to say each leaf is separated from the one 



next above it by three-eighths of 

 the circumference of the stem, so 

 that in following the spiral three 

 times round the stem we pass 

 eight leaves, and find that the 

 ninth lies vertically above that 

 from which we started (see Part 

 I. p. 14). The leaves themselves 

 are inserted on the stem with a 

 fairly broad base ; they are ovate 

 in form, pointed at the tip, and 

 traversed by a distinct midrib, 

 though not otherwise veined (see 



Fi & 68).. The rhizoids are white 



a fruiting specimen, g, when quite young, but soon be- 

 K JX'frSt or come brown. The above descrip- 

 sporophyte generation, tion applies especially to the barren 



consisting of the seta, s. -i -\-\ e *.- 



and the theca, th ; c, the stems ; we shall refer more parti- 

 calyptra. Slightly mag- cularly later on to those which 



nined. (After Sachs.) , , 



bear the reproductive organs. 



1. THE LEAFY STEM 

 a. Structure 



The anatomy of the Moss plant, as represented by 

 Funaria, is simple, but yet shows a fairly well-marked 

 differentiation of tissues. In the mature stem three 

 distinct zones can be distinguished, epidermis, cortex, 

 and central cylinder. The epidermis is one cell thick in 

 most places, though here and there a double row of cells 



