236 



BOTANY. 



hyphffi, which produce few or many separable reproductive 

 cells — the spores (Kg. 158). The method of formation of 

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

 phse, which are filled with protoplasm, become enlarged at 

 St* Ni the top, and in each 



a transverse partition 

 forms {A, a, Mg. 159), 

 the portion above the 

 partition {i, Kg. 159) 

 becomes larger, and, 

 at the same time, the 

 transverse partition 

 arches up (B, a. Fig. 

 159), finally appearing 

 like an extension of 

 the hypha, then called 

 the Columella (C, a, 

 Fig. 159). The pro- 

 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- 

 «3ell is now a sporangium. 



In the other Moulds the process is essentially like that 



Pig. 158.— Diagram showing the mode of growth 

 «of Miicor Mucedo. m, the mycelium: 5, single 

 ifiporangium, borne on an aerial erect hypha.— After 

 Prantl. 



an Mucor Mucedo. In 

 many cases there are sev- 

 eral sporangia formed at 

 the top of the vertical 

 liyjjhge ; in such cases the 

 latter are branched before 

 the formation of sporan- 

 gia. Another variation 

 from the method as de- 

 scribed above is that in 



A 



Fig. 159.- 



Diagi-ams showing mode 

 growth of Ihe spiiranginm of Mucw Mucedo. 

 A, very youns; ►tage ; B. somewhat later ; C, 

 T , sporangium uith ripe spores, a in all the fig- 



■SOme species but one spore ures represents the partition wall between the 

 £ J • 1 last cell of the iilament and the sporangium b. 



IS formed m each sporan- ^ * 



gium ; the hyphse then appear to bear naked spores. 



317. — The spores are set free in difPerent ways ; in some 

 •cases the wall of the sporangium is entirely absorbed by the 

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



