236 



BOTANY. 



hyphae, which produce few or many separable reproductive 

 cells the spores (Fig. 158). The method of formation of 

 the spores in Mucor Mucedo is as follows : the vertical hy- 

 phai, whicti are filled with protoplasm, become enlarged at 



the top, and in each 

 a transverse partition 

 forms (A, a, Fig. 159), 

 the portion above the 

 partition (b, Fig. 159) 

 becomes larger, and, 

 at the same time, the 

 transverse partition 

 arches up (B, , Fig. 

 159), finally appearing 

 like an extension of 

 the hypha, then called 



Fig. 158.-Diagram showing the mode of growth the Columella (C, a, 

 of Mucor Mucedo. m, the mycelium: g, single TTirr 1 ^\ Thp nrr 

 sporangium, borne on an aerial erect hypha.-After r J &' 1 J >" 



Prantl - toplasm in the en- 



larged terminal cell (b) divides into a large number of 

 minute masses, each of which surrounds itself with a cell- 

 wall ; these little cells are the spores, and the large mother- 

 cell is now a sporangium. 



In the other Moulds the process is essentially like that 

 in Mucor Mucedo. In 

 many cases there are sev- 

 eral sporangia formed at 

 the top of the vertical 

 hyphae ; in such cases the 

 latter are branched before 

 the formation of sporan- 

 gia. Another variation 

 from the method as de- 

 scribed above is that 111 5l, very youn-r stage -~B. somewhat later; C. 

 , eporanu'intn with npr Mporen. a in all the ng- 



SOme SpeCieS but One Spore ures represents the partition wall between 



-j v last cell of the filament s 



is formed in each sporan- 



and the sporangium b. 



gium ; the hyphae then appear to bear naked spores. 



317. The spores are set free in different ways ; in some 

 cases the wall of the sporangium is cnlircly absorbed by the 

 time the spores are mature ; in other cases only portions of 



