MFCOR. 293 



The conjugating hyphae belong to different strains of 

 Mucor mycelia, which we may simply call "male" and 

 "female"; when male and female mycelia come together 

 zygospores are formed, and any given mycelium produces 

 gonidia which give rise to mycelia of the same nature as 

 the parent mycelium. 



This apparently applies to the majority of the Mucor- 

 aceae, but in some forms, e.g. Sporodinia grandis, zygo- 



rres are produced by the conjugation of hyphae of 

 same mycelium. In Mucor, the conjugating hyphae 

 are formed on the portion of the mycelium which rami- 

 fies through the substratum, but in Sporodinia they are 

 formed on erect aerial hyphae. 



Sporodinia grandis grows as a parasite on several of the 

 larger freshy toadstools (Hymenomycetes), such as Boletus 

 (a pore toadstool), as a greyish fluffy mycelium, on which 

 the reddish zygospores can be seen with the naked eye. 

 It is common, and readily found in late summer and 

 autumn. 



Sporodinia can easily be cultivated indoors, and some 

 interesting observations can be made on it. Pour some 

 water into a wide-mouthed jar, and put filter- or blotting- 

 paper round the inside of the jar, so as to keep the sides 

 moist, then place a small beaker or dish, without any 

 water, in the bottom of the jar ; in the beaker place a 

 small bit of bread moistened with prune juice, and inject 

 the bread with Sporodinia gonidia or a piece of the 

 mycelium itself sections of Carrot root may be used with 

 advantage instead of bread. Cover the jar with a sheet of 

 glass, and examine the culture from time to time ; the 

 zygospores appear in a few days. 



Note that the gonidiophores of Sporodinia differ from 

 those of Mucor in being dichotomously branched, each 

 branch ending in a small gonidangium. 



The zygospores are formed by conjugation between erect 

 hyphae. Where two hyphae are close together, there 

 arises from each an outgrowth, like the conjugating tubes 

 of Spirogyra, and these become swollen at the ends. When 

 the swollen tips come into contact, each tip is cut off by a 

 cross-wall from the rest of the tube (which is called the 



