GENERAL INFORMATION 7 



covering — the wall of the spore. There are a 

 variety of types, but for convenience we may class 

 them under two heads : — 



(a) Those which are formed as a result of some 

 sexual union, e.g. oospores, zygospores, etc. 



(d) Those formed asexually, i.e. not — so far as is 

 known — by any sexual act, e.g. conidia, endospores, 

 chlamydospores. 



Under each of these heads the shape of the 

 spores is very varied. They may be : — 



Round as in Penicillmm glauciun, 



Oval as in Mucor mitcedo, 



Angular as in Oidium lactis, 



Crescent shaped as in Pusarhwi solaniy 



Needle shaped as in Claviceps ptcrpitrea (asco- 

 spores). 



Kidney shaped as in many Basidiomycetes ; 

 indeed, diversity in shape may be noticed in spores 

 growing side by side on the same branch. Irre- 

 spective of the shape, most fungus spores are easily 

 carried in the atmosphere from place to place ; 

 where they may either be capable of immediate 

 germination, or they may remain dormant for a 

 considerable time prior to growth. In either case 

 a new centre of infection is set up by each individ- 

 ual spore thus carried. 



Germination of Spores. — The germination of 

 spores, and the growth of a fungus generally, are 

 best studied by making what are called drop cul- 



