4 6 



A TEXT-BOOK OF BOTANY. 



number of species of Mucor have the power of inducing alcoholic 

 fermentation in glucose-containing solutions. They are also 

 commonly found in many aqueous solutions of inorganic chemicals 

 as well as organic substances. Asexual spores are formed at the 

 ends of hyphse which rise into the air. The sporangia are spherical 

 and are cut off from the hyphae by means of a transverse wall 

 which projects upward into the sporangium and which is techni- 

 cally known as the columella (Fig. 23, A). The contents by 



n 



V 



FIG. 24. Peziza confluens showing stages in the development of ascospores. In the 

 youngest asci (m, r) there is only one nucleus; this divides into two (s) ; the division is 

 repeated, so that there are 4 nuclei in (t) and 8 in (n). These surround themselves with 

 protoplasm and a cell-wall (v, w), but the protoplasm of the mother cell or ascus is not entirely 

 used up. After De Bary. 



simultaneous division form numerous i -celled spores, which are 

 discharged by the bursting of the sporangium wall and distributed 

 by air-currents or the wind. As the name of the group to which 

 this plant belongs indicates, it also produces zygospores (Fig. 

 23, D). These are formed by hyphal branches which ascend 

 from the substratum. The ends of two branches come together, 

 a transverse wall is formed in each branch, the walls in contact 

 are absorbed, the contents unite, and a spore is formed with 



