348 DIVISION III. MODE OF LIFE OF THE FUNGI. 



special examples of the general rules regarding capability of germination, resistance, 

 &c. which hold good in those organs. 



The theoretical explanation of the phenomena is therefore the same as in 

 analogous cases outside the Fungi and presents the same difficulties. This is not the 

 place to discuss this question, and the reader is therefore referred to physiological 

 works, and especially to the chapter which deals with it in Pfeffer's Physiology. 



It is hardly necessary to call attention once more to the consideration, that the 

 particular phenomena and characters change or may change from one case to another, 

 and that consequently the phenomena to be expected in one Fungus-spore cannot be 

 concluded with certainty from those of another, though it may be an allied form ; each 

 must be investigated for itself. This applies as much to spores of the same name in 

 different species of Fungi as to differently named spores in the same species. More- 

 over the results of enquiries into persistence and resistance show individual differences 

 in similar spores. For we not only see germination more difficult and slower under 

 otherwise similar conditions near the limits of persistence and resistance-^the gonidia 

 of Aspergillus flavus, for example, germinate at once when fresh, but not till the 

 conditions for germination have been in operation for fourteen days when they have 

 been kept in a dry state for six years, but some spores die sooner when approaching 

 those limits than other similar ones. These differences may be due to internal 

 causes which may perhaps be summed up in the words dissimilar maturation ; or 

 possibly, after similar maturation, some spores are better protected than others against 

 slowly operating and modifying causes acting from without, and this it is extremely 

 difficult or impossible to determine with certainty 1 . But we must certainly not 

 disregard these differences when dealing practically with the question, and it is possible 

 that they have been the occasion of some of the discrepancies in the foregoing 

 statements. 



There is another point which is also sufficiently obvious, namely, that the 

 characters described above imply adaptations, sometimes of a rougher, sometimes of a 

 more delicate kind, to definite modes of life. Two instances of this may be given. 

 The spores of ordinary Moulds, of Penicillium, Eurotium, Aspergillus, and the Mu- 

 corini, and the gonidia of many Ascomycetes, which are capable of germination as 

 soon as they are ripe and are also of a hardy nature, continue when they are once 

 matured to be for a long time always ready for further development if they meet with 

 the necessary conditions, and this, it may be said, may happen at any spot and at 

 any time in the case of these Fungi, because they have a very wide field of choice as 

 regards the nature of the substratum (see section XCVII). The teleutospores of Puccinia 

 graminis, which were described above as passing normally through the winter in a 

 dormant state, find the most favourable conditions in the ensuing spring, when their 

 power of germination is at its best, not only for germination but also for the further 

 development of the short-lived sporidia, which are the products of their germination ; 

 the conditions are favourable to the sporidia, because the danger of desiccation is 

 comparatively small in the moist cool spring-time, and there is young foliage on the 

 Berberis-plants into which the germ-tubes from the sporidia must penetrate to secure 

 their further development (see section CX). In autumn, when the teleutospores are 



1 See on this point for example v. Liebenberg, as cited on page 344. 



