GROUP 1. THALLOPHTTA : FPNGI : BASIDIOMYCETES. 313 



The number of gonidia borne by a unicellular basidium is usu- 

 ally four; but it maybe one (species of Hymenogaster), or two 

 (Calocera, Dacryomyces, species of Octaviana and Hymenogaster), 

 or 4-8 (Phalloideae). In the case of the multicellular basidium, 

 each cell bears one basidiogoriidium. 



Simple gonidiophores have been discovered in several forms 

 (Pilacre Petersii, Auricularia sambucina and mesenterica, Exidia, 

 Ulocolla, Craterocolla, Sebacina, Tremella mesenterica and lutescens, 

 Tomentella, Exobasidium, Heterobasidium [Polyporus] annosnm 

 [Trametes radiciperda], Dacryomyces). In these forms the basidio- 

 gonidium gives rise, on germination, to a mycelium, sometimes 

 small and unbranched, which is either itself the simple gonidio- 

 phore, or bears simple gonidiophores, on which gonidia are formed 

 by abstraction. The same mycelium may subsequently bear the 

 compound gonidiophores ; or the gonidia-bearing form may repro- 

 duce itself through successive generations until at length, under 

 appropriate conditions, the form bearing the compound gonidio- 

 phores occurs. In the genus Craterocolla, the simple gonidio- 

 phores are collected into sori developed in special receptacles. 



The gonidia of Tremella, cultivated in nutrient solution, mul- 

 tiply rapidly by budding, producing yeast-like cells, which have 

 not, however, the power of exciting alcoholic fermentation. 



The formation of unicellular gemmse (see p. 274), is of common 

 occurrence in the Basidiomycetes; either in the form of chlamydo- 

 gonidia (e.g. Nyctalis, Oligoporus, Fistulina), or, more commonly 

 (e.g. Ulocolla, Dacri/omyces deliquescens, species of Coprinus, Cla- 

 varieoe, Lenzites, Pholiota, Collybia, Nyctalis, Phlebia, Polyporus, 

 Cyathus, etc.) in the form of oidium-cells. The chlamydogonidia 

 are especially developed in the basidial fructifications of the 

 plants in which they occur : the oidium-cells are generally de- 

 veloped from the vegetative mycelium, either the whole of it or 

 individual hyphse, forming sometimes a more or less definite fruc- 

 tification (Dacryomyces deliquescent). In some Agaricinaa (e.g. 

 Coprinus, Clavariece, Stropharia stercoraria, Psathyrella, etc.) 

 the oidium-cells appear to be incapable of germinating. 



Sclerotia (see p. 275) are known in some cases. The mycelium 

 (e.g. Typhula variabilis, and com planata, Coprinus stercorarius, 

 Tulostoma) produces sclerotia as an antecedent to the formation 

 of the compound gonidiophores ; the sclerotia become quite free 

 from the mycelium, and may be kept for months without losing 

 their vitality. On germination each sclerotium gives rise to one 



