352 DIVISION III. MODE OF LIFE OF THE FUNGI. 



of this work (page 240) altogether out of the question, we may quote here, as 

 examples only, the basidiospores of most Gastromycetes (Phalloideae, Lycoperdaceae, 

 Hymenogastreae), and the ascospores of Tuber, Elaphomyces, and allied genera, organs 

 which in contrast with the more or less doubtful spermada are quite certainly 

 homologous with allied forms which germinate readily. To these may be added 

 the zygospores of Mucor stolonifer, Brefeld's Mortierella Rostafinskii. The germination 

 of Agaricus campestris also has never been certainly observed 1 . The number of cases 

 of this kind has gradually diminished, the more it was recognised that the conditions 

 of germination or adaptations might vary from one species to another and the more 

 these conditions were ascertained in particular cases. This must be considered in judging 

 of unsuccessful experiments in germination, and may lead us to expect success from 

 further investigations in cases where it has hitherto been wanting. On the other hand, 

 phenomena such as those pointed out on page 332 in connection with Sphaerobolus must 

 not be disregarded. 



The sporocarps of Erysiphe which were closely studied by Wolff 2 show that in 

 germination as elsewhere adaptations may occur which deviate considerably from those 

 ordinary cases of adaptation on which our views are apt to be founded. These arrive 

 at maturity, that is, separate from the nutrient substratum with the termination 

 of the period of vegetation. At this time the asci are formed inside them and in 

 most species the spores also are formed in the asci, but in some (E. graminis, E. 

 Galeopsidis) no spores are yet formed. In this condition the sporocarp enters upon 

 its winter's rest. When this is over and the sporocarp is placed in water, the spores 

 are formed and ripen in E. graminis and E. Galeopsidis, in other species, as E. communis, 

 they ripen only ; then the spores are at once discharged from the sporocarp which 

 bursts by the swelling of its contents, and the spores germinate. In this case therefore 

 the mature sporocarp hibernates, provided, as minute investigation shows, with reserve 

 material for the subsequent formation of the spores, and the spores, even those which are 

 apparently and which were formerly supposed to be ripe before hibernation, do not really 

 mature and acquire the capacity for germination till after the winter rest is over. In 

 contrast to this proceeding most other homologous sporocarps form mature spores 

 with the power of germination either without passing through a resting stage or before 

 they enter it, or else they become dormant before the formation of the asci when they 

 are in form like a sclerotium or xyloma. It is not yet ascertained whether there are 

 not species even of Erysiphe which dispense with a period of rest. Tulasne's 3 account of 

 E. guttata seems to point in this direction. 



CHAPTER VII. PHENOMENA OF VEGETATION. 



1. GENEBAL CONDITIONS AND PHENOMENA. 



SECTION XCVII. Fungi resemble all other plants in the main features of 

 their organisation and material composition ; it may be assumed therefore beforehand, 

 and the assumption is confirmed by experience, that the most general conditions of 

 vegetation are the same in both classes, which may therefore in general terms be said 

 to be dependent in the same manner on light, heat, gravitation, and the chemical 



1 See Nylander, Flora, 1863, p. 307. 



2 As cited on p. 294. See above, pages 76 and 202. 



3 Carpol. I. 



