496 



LIFE-HISTORIES 



upon the surface of some nutrient medium germinates by- 

 sending out one or more projections (Figs. 325, 3), and these 

 finding abundant food available elongate and l)ranch indef- 



FiG. 324. — Pin-mold {Mucor Mucedo, Pin-mold Family, Mucoracew). 

 Plant showing the much-branched horizontal mycelium from which 

 arise pin-like vertical hyphse (a, h, c, of different ages) that eventually 

 develop dust-spore-cases at the tip. Somewhat magnified. (Zopf.) 



Ul 2 



Fig. 325. — Pin-mold. 1, dust-sporo-case, viewed as if cut vertically, 

 showing the tip of the vertical hypha (c) projecting into the spore-case; 

 the spore-case wall (m); and the numerous dust-spores (sp), •i^. 

 2, same from which the dust-spores have been shed. 3, germinating 

 dust-spore, m". (Brefeld.) 



initely so long as the conditions are favorable. Soon there 

 may be as complex a system of branches as that in Fig. 324. 

 A fungus thread is termed a hypha.^ The mass of hyphse 

 forming the vegetative part of a fungal thallus constitutes 

 ' Hy'pha < Gr. hyphe, a web. 



