374 FUNGI 



been found impossible to trace any anatomical distinction between these 

 elements, and therefore it amounts to no more than a probability that 

 the hyphae from the coil are the ultimate ascogenous hyphae ; while those 

 from the tissue of the sclerote may furnish the envelope-tissue of the 

 sporocarp. The main difference between the development of S. sclero- 

 tiorum and S. Fuckeliana in this respect consists in the primordial coil 

 of the latter originating not within the sclerote, but in the central portion 

 of the bundle of stalk-hyphs after it has reached the external surface. 



S. sclerotiorum possesses, so far as is known, no intervening acro- 

 spores. The germinating ascospore produces a mycele on which sclerotes 

 are formed, and on these only the sporocarps again. S. Fuckeliana 

 sometimes does the same, and de Bary has observed a single instance of 

 the sporocarp being produced on the mycele without even the formation 

 of a sclerote. The sclerotes of this species, however, frequently produce 

 filamentous sporophores bearing acrospores, this stage being that 

 formerly known as Botrytis cinerea (Pers.). It never happens that a 

 sclerote bears both acrospores and sporocarps, either together or after 

 each other. The primary mycele may bear acrospores directly without 

 interfering with the subsequent production of sclerotes, but this does not 

 happen often. The mycele produced by the germinating acrospores is 

 similar in all respects to the primary one arising from the ascospore, with 

 the reservation that it has a greater tendency than the other to the pro- 

 duction of sporophores. In this species there are also often formed 

 certain abortive acrospores, or it may be poUinoids. 



12. Pleospora (Rabenh.). — In the origin of the perithece of Pleo- 

 spora herbarum (Rabenh.), the traces of sexuality disappear from view, 

 and indeed it is stated that the asci arise among the paraphyses as 

 branches of the basal cells of the latter. In the life-history of this 

 fungus a considerable number of forms are embraced. Besides the 

 ascospores, which are compound multicellular bodies, there are in the 

 second category acrospores of three sorts, viz. (a) Double or multicellular 

 acrospores of rounded short cylindrical form, previously taken to be an 

 independent species (Macrosporium Sarcinula, Berk.). Each such com- 

 pound spore appears as a rule singly on its sporophore. {U) Conical pear- 

 shaped likevnse compound spores appearing in series, often in branching 

 series. This was also formerly described as an independent species of 

 Alternaria (Nees ab Esenb.). (c) A small form of acrospore recorded by 

 Bauke, but not, according to de Bary, Cladosporium herbarum (Link), 

 which, though placed in genetic connection with Pleospora herbarum by 

 Tulasne, does not belong here. In the third category there are pycno- 

 spores formed in pycnids interstitially arising on mycelial hyphae. The 

 pycnids consist of a wall of several layers, from the inner surface of 



