DIV. I 



MORPHOLOGY 



In some Mosses there are in addition elongated and pointed mechanical cells which 

 closely resemble sclerenchyma fibres. 



(e) Gametophyte of the Cormophytes ( 53 ). In the developmental 

 history of the cormophytes a stage with a thalloid vegetative body 

 occurs. Two generations alternate regularly with one another, the 

 spore-bearing plant or sporophyte and the sexual plant or gametophyte. 

 The vegetative body of the former is a connus, while that of the latter 

 is usually a very simply segmented and constructed thallus (pro- 

 thallium). In Pteri- 

 dophyta the gametophyte 

 is usually a flat green 

 // structure attached to the 



soil by rhizoids and living 



FIG. 06. Transverse section of the stem of Mnium undu- 

 latum. I, Conducting-bundle ; c, cortex; e, peripheral 

 cell layer of cortex ; /, part of leaf ; r, rhizoids. ( x 90. 

 After STRASBURGER.) 



FIG. 97. Asjndium filix mas. Pro- 

 thallium from the lower side. 

 rh, rhizoids. (x about 8. After 

 SCHEXCK.) 



independently (Fig. 97). It is at most a few centimetres in length 

 and resembles a small Liverwort thallus. It may also consist of 

 branched filaments. 



B. THE CORMUS 



The vegetative organs of the sporophyte in the Ferns and fern-like 

 plants (Pteridophyta) and in the Spermatophyta, to which the name 

 cormus will be applied, are, as has already been mentioned, more 

 highly segmented than the thalli. The cormus is divided into shoot 

 and root, the shoot into the axis and the leaves. Stems, leaves, and 

 roots are thus the fundamental organs of the cormus, which evidently 

 is adapted to life on land by its outer and inner construction. 



