3i6 FUNGI 



optimum temperatures at which the actual germination of spores takes 

 place. According to AViesner the minimum for the spores of Penicil- 

 lium glaucum (Lk.) is from i'5° C. to 2°, the optimum about 22° C, and 

 the maximum 40° C. to 43' This may be taken as fairly illustrative of 

 other fungi in temperate countries in the open. Those which germinate, 

 like many Mucorini and fungi inhabiting excrement, in the digestive 

 tract of warm-blooded animals, have a much higher minimum, and an 

 optimum agreeing with the body temperature. A supply of water and 

 of oxygen must accompany the favourable temperature in all cases, and 

 of nutrient substances in some. Speaking generally, parasites germinate 

 freely in pure water or vapour, and saprophytes in nutrient substances, 

 but the spores of many fungi germinate in both. 



Conditions of Vegetation. 



Under this head it will be necessary to consider little else than 

 the nutritive adaptation of fungi, since they resemble other plants in 

 the general conditions of vegetation, in their dependence on tempe- 

 rature, light, &c. The optimum temperature varies, as might be ex- 

 pected, in the cases of fungi which flourish at different seasons of the 

 year, and in different climates. The optimum temperature for the 

 growth of mycele in Penicillium glaucum is about 26° C, while that 

 of spore-formation is the same as that of germination, about 22° C. 

 These figures may be taken as fairly illustrative. 



Luminosity ' is exhibited by a considerable number of fungi — Agari- 

 cus olearius (DC.) and the rhizomorph form of A. melleus, Polyporus 

 annosus (I-'r.), and P. sulphureus (Fr.) (Europe), Agaricus igneus (Tul.) 

 (Amboyna), A. noctilucens (Lev.) (Manilla), A. Gardneri (Berk.) (Brazil), 

 A. lampas (Berk.) (Australia), A. Emerici (Berk.) (Andaman Islands), a 

 species of Didymium (Jamaica), and probably by a number of other forms, 

 the evidence as to which is doubtful. It is a phenomenon dependent upon 

 the life of the organism, and the progress in it of destructive metabolism. 



As regards nutrition, the absence of chlorophyll and the consequent 

 inability to decompose carbon dioxide drive fungi to seek for organic 

 carbon-compounds. In taking up food, fungi cause chemical changes 

 in the organic bodies which furnish the food, e.g. fermentation. The 

 well-known ferment-fungi need only be mentioned. It is in the highest 

 degree probable that the solvents secreted by such fungi as penetrate 

 dense woody and other structures are ferments. All fungi may be 



' A'ines, Lectures on the Physiology of Plants, p. 317 ; see also Phillips, Proc. 

 Woolhope Club, 1888. 



