MONOGRAPH OF TIIE LABOULBENIACE^E. 



251 



PART IT. 



NOTE CONCERNING THE SYSTEMATIC POSITION OF THE LABOULBENIACE^E. 



The systematic position of the Laboulbeniaceae has been a matter of much un- 

 certainty, and even in the light of a fuller knowledge, both of the forms and of their 

 development, it still remains undetermined what are their immediate connections 

 within the group of Ascomycetes to which they must undoubtedly be referred. As 

 we have seen, Montagne and Robin (1853), who were the first to describe them as 

 plants, speak of the single genus then known as " e familia Pyrenomycetum novum 

 genus," and compare it to Capnodium, although they made no observations on the 

 origin of the spores. Later, Karsten, who first included them in the Mucorini (1869)? 

 places them (1895) in a group of " Stigmatomycetes," between the Ustilaginese and 

 the Pyrenomycetes ; but although this author correctly observed the essential fact of 

 the occurrence of fecundation, he denies the presence of asci, and gives a quite errone- 

 ous account of the spore formation. Peyritsch (1871, 1873), although his observa- 

 tions on the process of fecundation were incorrect, was the first to present any definite 

 evidence of their ascomycetous nature ; yet it seems doubtful whether asci were seen 

 even by him, since his reference to them as "eight to twelve spored " indicates the 

 correctness of the criticism made by Karsten, who held that these " asci " were 

 merely the ordinary aggregations of spores, coherent in a fusiform mass, as is their 

 wont, and surrounded by their own gelatinous envelopes, which were mistaken for the 

 ascus wall. This element of uncertainty in the observations of Peyritsch led De Bary 

 to place the group among his " Doubtful Ascomycetes," a disposition in which he has 

 been followed by most systematists who have alluded to the group at all. In any 

 case, it is at present definitely determined that asci, containing four or very rarely 

 eight spores, always occur ; and that they are beyond question the morphological 

 equivalents of the corresponding structures in the Ascomycetes generally. It further 

 seems undeniable that these bodies are of sexual origin, in view of the evidence 

 adduced in the foregoing pages. If, then, we admit both the sexual and the asco- 

 mycetous nature of these plants, their consideration becomes a very important factor 



