214 



REPRODUCTION 



a very early period of its develogment, d, we find the sporangium 

 composed of a protoderm and a central cell. The protoderm 

 proceeds to the formation of an epidermis or sporangium wall, 



TT^< ^5i C3" i * >-^ t4 ■O/js, / \ sporangium wall 

 shesporlal cell \ x~-~^ >~l \ j„''lV) J \ 



Mature tapetum of 

 Itwo cell-layers 



Tapetal Plasmodium 



formed by fusion of 



tapetal protoplasts v,^ i / , , , v, ^ ^^^ 



' i. — J i— < A»e, 1 r<»»=t — _ v-jf' 1/ Mother cells have divided 



to form four spores only 

 three shown 



Grandmother-cell has divided 

 producing two mother-cells 



Fig. 12 2. — Sporangium and spore formation of a fern, Aneimia Phyllitidis. a, growing 

 apex; i, group of three protodermal cells which are to give rise to a sporangium; h, c, d, e, 

 f, g, h, successive stages in sporangium and spore formation. Partly diagrammatic. 

 Further description in the text. 



