344 DIVISION III. MODE OF LIFE OF THE FUKGI. 



of germination for a short time only after completing their brief period of swarming 

 and die if the conditions are unfavourable to germination. But the diplanetic spores 

 in these groups (see pages 108, 143) are to some extent exceptions to this rule, since 

 they may continue alive and unaltered for days and weeks, perhaps longer, after 

 entering upon the transitory period of rest, if the conditions required for their further 

 development, especially a sufficient supply of oxygen, are excluded. Further de- 

 velopment begins if they are placed in fresh water containing oxygen, and first of 

 all the second stage of swarming. 



But many spores of this first category, belonging to Fungi which do not live in 

 water, retain their vitality and power of germination for a long time, if they are 

 protected and kept in an air-dry state. 



It has been proved that the spores of many common Fungi will remain alive for 

 a period varying 1-2 years ; for example the ascospores of Penicillium glaucum have 

 germinated when two years old, the gonidia after i- if years; the spores of 

 Coprinus stercorarius 1 when more than i year old, the gonidia of Aspergillus niger 

 when of the same age, of Sordaria curvula after 28 months, of Botrytis Bassii and of 

 allied forms of Isaria after 1-2 years, of Mucor stolonifer after i year. The gonidia 

 of Phycomyces nitens, a species nearly related to Mucor Stolonifer, is a good 

 example of specific and individual variation. Van Tieghem 2 found that they hardly 

 retained their vitality for 3 months, and I once observed the germination of gonidia 

 which were 10 months old, while others had lost their vitality after the space of i 

 month. 



The resting-spores of some Ustilagineae are very long-lived according to 

 Hoffmann and v. Liebenberg 3 ; the latter observer found the spores of Tilletia Caries 

 from a herbarium specimen capable of germination after 8| years, those of Ustilago 

 Carbo after 7^ years, of U. Tulasnei and Urocystis occulta after 65, of Ustilago 

 Kolaczeckii, U. Crameri and U. destruens after 5^ years, of U. Rabenhorstiana 

 after 3^ years. In some of the forms here mentioned, as U. Carbo, the maximum 

 of possible duration appears to be given; in others as Tilletia Caries the vitality 

 may continue beyond the time specified, which is given for the oldest material at 

 command, and this showed such active power of germination that it may be assumed 

 that still older spores would have retained the power. 



Gonidia of Aspergillus flavus * proved in one case to be capable of germination 

 after having been kept in a dry state for 6 years, those of A. fumigatus 8 for as many as 

 10 years. 



Well-known examples of spores which require to go through a period of 

 rest before they are capable of germination are found in the oospores of the Pero- 

 nosporeae and most Saprolegnieae, the zygospores of the Mucorini, the organs 

 described above as resting-spores in the Chytridieae, Protomyces, and other forms, 

 the teleutospores of most Uredineae with the exception however of Leptopuccinia, 



I Brefeld, Schimmelpilze, II, 76; III, 15. 



II Van Tieghem et Le Monnier in Ann. d. sc. nat. ser. 5, XVII, 288. 



8 Hoffmann, in Pringsh. Jahrb. II, 267. v. Liebenberg, Ueber d. Dauer d. Keimkraft d. Sporen 

 einiger Brandpilze (Oesterr. Landw. Wochenblatt, 1879, ^ r - 43; 44)- 

 4 Brefeld, Schimmelpilze, IV, p. 66. 

 * Eidam, in Cohn's Beitr. z. Biolog. Ill, 347. 



