STRUCTURE OF SPORES 



161 



and give it the appearance of being closely covered with 

 short cilia (D 2 ). 



In the ripe sporangium the slightest touch suffices to 

 rupture the brittle wall and liberate the spores, which are 

 dispersed by the swelling of the transparent intermediate 

 substance. The aerial hypha is then left terminated by the 

 columella (E), around the base of which is seen a narrow 

 black ring indicating the place of attachment of the 

 sporangium. 



The spores (F) are clear, bright-looking, ovoidal bodies 



FIG. 38. Moist chamber formed by cementing a ring of glass or 

 metal (c) on an ordinary glass slide (A), and placing over it a cover-slip 

 (B) on the underside of which is a hanging drop of nutrient fluid (p). 

 The upper figure shows the apparatus in perspective, the lower in 

 vertical section. (From Klein.) 



consisting of protoplasm containing a nucleus and surround- 

 ed by a thick cell-wall. A spore is therefore an ordinary 

 encysted cell, quite comparable to a yeast-cell. 



The development of the spores is a very instructive process, 

 and can be easily studied in the following way : A glass or 

 metal ring (Fig. 38, c) is cemented to an ordinary microscopic 

 slide (A) so as to form a shallow cylindrical chamber. The 

 top of the ring is oiled, and on it is placed a cover glass (B), 

 with a drop of Pasteur's solution on its under surface. 

 Before placing the cover-glass in position a ripe sporangium 



M 



