lyS 



RESEARCHES ON FUNGI 



on to cleared dung-agar in a Petri dish. Here many of them 

 germinated within twenty-four hours. The monosporous mycelia 



soon came into contact 

 and fused with one 

 another, so that a fine- 

 meshed compound my- 

 ceHum was eventually 

 formed. Part of this 

 mycelium is shown in 

 Fig. 104. In the for- 

 mation of a large fruit- 

 body on horse dung in 

 the field under natural 

 conditions it is probable 

 that the mycelium is 

 often, or even usually, 

 compound. Doubtless in 

 such a compound my- 

 celium, while two mono- 

 sporous mycelia only are 

 concerned with the sex- 

 ual phenomena leading 

 to the production of the 

 fruit-body (the species 

 is heterothalhc), the 

 other monosporous my- 

 celia forming part of 

 the compound myce- 

 lium contribute socially 

 to the development of 

 the fruit-body and to 

 the production of its 

 spores by yielding up 

 to the fruit-body their 

 nutritive contents. 

 As an example of the existence of hyphal fusions in one of the 

 Fungi Imperfecti in which the perfect fruiting stage is unknown 



Fig. 102. — Pleurage anserina, one of the Pyrenomy- 

 cetes. To show hyphal anastomoses between 

 myceUa derived from different dwarf spores. 

 A, the mycelium a a was derived from one dwarf 

 spore and the mycelium b b from a dwarf spore 

 of opposite sex. The mycelium 6 6 in the region 

 n has become netted, and one of its hyphae has 

 fused with a hypha of the mycelium a a atj. 

 The arrows along the hyphae indicate the direc- 

 tion of growth. B, similar to A : a hypha of 

 the mycelium a a has become united to a hypha 

 of the myceliinn b b ; the junction has been 

 effected atj by means of short bridging hyphae. 

 Drawn by A. H. R. Duller and E. Silver Dow- 

 ding. Magnification, 400. 



