ASEXUAL REPRODUCTION 101 



V 



conidial form of reproduction. The ascigerous form of 

 fruit, which usually enters on a period of rest before it is 

 capable of germination, is more especially for the purpose 

 of continuing the species in time ; it tides over that period 

 when conditions are unfavourable for the continued growth 

 of the individual. 



Zoospores, produced by many of the Phycomycetes, 

 perform the same function for species as that stated for 

 conidia. It may be noted, however, that some zoospores 

 are also produced in fruit of sexual origin, as in Cystopus. 



Oidia are very minute conidia-like reproductive bodies 

 usually produced in chains, and terminal on the first formed 

 tubes of a germinating spore. Our knowledge of these 

 bodies is mainly due to the researches of Brefeld. Biffen 

 has shown that in Collybia velutipes, the hyphae produced 

 by germinating spores soon break up into oidia-chains. 

 When the hyphae of this fungus has formed a small my- 

 celium in the vessels and tracheids of a piece of wood, it 

 becomes broken up into oidia which germinate quickly, 

 and thus the wood is permeated by a large quantity of 

 mycelium in a short time. 



I have observed the formation of long chains of 

 oidia terminating the germ-tubes of conidia of Botrytis 

 cinerea. 



In the host of forms included under ' fungi imperfecti ' 

 the reproductive bodies should properly be called conidia, 

 although the term spore is common in systematic works. 

 In some systematic works the term spore is applied to all 

 reproductive bodies of exogenous origin, as basidiospores, 

 etc., and the term sporidia to all spores of endogenous 

 origin, as ascospores, etc. 



As an exception to the general statement that conidia 



