INTRODUCTION TO CRYPTOGAMIC BOTANY. 247 



necessary consequence, that there should be no genuine species 

 of Oidium. In the same way it is quite clear that many 

 species of Sphceropsis, Phoma, and other acrosporous sphajri^- 

 form Fungi, are merely states of true Sphwrice and their allies. 

 In some cases the proper fruit of Diplodia and Tympanis 

 grows on the same hymenium, as observed by myself and Mr. 

 Broome ;* but, as before, it is not matter of necessity that there 

 should be no genuine species of such genera. While, there- 

 fore, we recognise this diversity of modes of reproduction, the 

 essential weight of the external or internal production of spores 

 will not be affected ; and while the general arrangement will 

 comprise equally natural groups, we shall be in a condition 

 to understand exceptional cases more correctly. 



238. Very important discoveries have been made very 

 recently by Tulasne, Caspary, and others, respecting the fruit 

 of certain moulds. Many of those species of Botrytis, for 

 instance, which were separated by Corda under the name of 

 Feronospora, and of which the potato mould and cabbage 

 mould (Fig. 23) are examples, bear also amongst their myce- 

 lium large globose bodies, which are evidently a second form 

 of fruit. Artotrogus, Mont, is probably one of these bodies. 

 But, more than this, the common Aspergillus glaucus has a 

 secondary form of fruit, which is in fact the well-known 

 Hurotium, which in its perfect state is ascigerous. The facts 

 which have been ascertained are at present too few to warrant 

 any general deductions. An attempt has been lately made ia 

 Hedwigia to show that Cladosporium herharum has spiral 

 spermatozoids, but the matter requires confirmation before it 

 can be admitted as a fact. 



239. At present, as far as I am aware, nothing more than 

 mere molecular motion has been observed in the representa- 

 tives of the spermatozoid granules, except, indeed, the genus 

 Saprolegnia be admitted into FungL It is probable, indeed, 

 that -they are merely representative, and that they are 

 capable of reproducing the species exactly as the zoospores of 

 Algse. 



* Hook. Journ. and Kew Misc., vol. 3, p. 319. 



