132 The Ottawa Naturalist [Dec. 



ing its kind. Reproduction of fungi is effected by spores which 

 when ripe leave the parent plant in various ways and which are 

 capable of growing independently into new plants. The sexual 

 development of fungus spores, similarly to the seeds of higher 

 plants is accurately known in a few instances. It is generallv 

 accepted that most fungus spores are produced asexually, that 

 is without egg and sperm cells. The simplest form of spore 

 production is that of the conidiospores. It takes place by the 

 rising up from the mycelium of a number of erect hyphae. all 

 of which produce at their tips a single or a series of spores. 

 These spore-bearing branches are known as conidiophores. Fre- 

 quently these conidiophores branch and each branch segment s it self 

 into successive spores. This is the case for instance in the fungus 

 causing the common potato disease Phytophthora injestans. In 

 other fungi the production of spores does not take place by this 

 act of segmentation, but the contents of the hyphae itself 

 generally form into spherical spores. In this way the smut 

 spores of grain are produced. 



A very common method of spore production is that in which 

 the spores are produced in separate tubes, small sac-like organs, 

 technically termed 'asci. These are much broader than the 

 hyphae and are generally club-shaped. Each ascus contains 

 from two to eight spores often more, but always an even number. 

 The spores produced in this manner are known as ascospores 

 and the whole group endowed with this method of reproduction 

 is known as ascomycetes. These forms of fungi are again sub- 

 divided according to the number of spores in each ascus and by 

 the manner the asci are produced, which may be singly as in the 

 Peach Leaf-curl fungus, or in flat or rounded discs as in peziza 

 or in fruiting bodies similar to pycnidia , but here termed 

 perithecia. These conditions of spore production may become 

 still more complicated, as even one species may produce several 

 kinds and crops of spores. 



The spores of microscopic fungi differ greatly in size and 

 form. Their colour is more generally hyaline or transparent, 

 but they may also be brown, grey, pink, etc. Their form varies 

 greatly: they may be oval, round, rod-shaped, or sickle-shaped, 

 with pointed or rounded ends. They may be of single cells, or 

 divided into two or many sections, smooth or pitted, with netlike 

 markings or appendages. Thus they will be found to be very 

 different objects, but their appearance is constant in each 

 fungus. These characters, together with the manner in which 

 they are produced are regarded as specific and generic distinc- 

 tions and are largely used for the purpose of classification. 

 When ripe the spores are shed in various ways, the conidio- 

 spores simply become detached and are carried by the air. 



