336 



BOTANY. 



hyphsB, 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- 

 phse, which are filled with protoplasm, become enlarged at 

 *t nJ the top, and in each 



a transverse partition 

 forms {A, a, Fig. 159), 

 the portion above the 

 partition {h, Fig. 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 {0, 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- 

 cell is now a sporangium. 



In the other Moulds the process is essentially like that 



Fig. 158. — Diagram showing the mode of growth 

 of Muc<yr Mucedo. m, the mycelium; «, single 

 sporangium, borne on an aerial erect hypha,— After 

 Prantl. 



in Mucor Mucedo. In 

 many cases there are sev- 

 eral sporangia formed at 

 the top of the vertical 

 hyphse ; 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.— Diagrams showing mode 

 growth of the sporangium of Mucor Mucedd. 

 At very young stage ; B, somewhat later ; C, 

 . , sporangium with ripe spores, flinallthefig- 



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

 t. -I • 1 last cell of the filament and the sporangium b. 



IS formed in each sporan- 

 gium ; the hyphse then appear to bear naked spores. 



317. — The spores are set free in different 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 



