996 RECORD OF CURRENT RESEARCHES RELATING TO 



Conidial Apparatus of Pleurotus ostreatus.* — Specimens of this 

 fungus gathered in the woods of Meudon on Feb. 1st last, exhibited 

 the following peculiarities of structure. 



The development of these specimens had taken place under 

 unfavourable conditions, in consequence of the severe cold of January, 

 which caused such an exuberant growth of the capiHary system that 

 the fungus, which ordinarily possesses only short hairs, and these 

 usually very few, on the pileus and the stipes, was entirely covered 

 with a dense white down. 



The hairs which constituted this down were composed of two or 

 three cells with granular contents and witli a swelling at each articu- 

 lation. The hairs were ordinarily distinct ; but sometimes two or 

 three had coalesced either at the apex or at the point of contact of 

 two lateral walls, or finally by means of a kind of bridge. 



The hairs on the centre of the pileus and on the stipes appeared 

 to be always sterile, while those on the edge of the pileus were shorter 

 and often sporiferous. These spores are ovoid, colourless, thin-walled, 

 and contain one or two vacuoles ; they are borne on a short sterigma. 

 Each hair bore one or two spores, but there was never more than one 

 attached to a single cell. The spore might be exactly terminal, or 

 near the summit, or altogether lateral. 



The fertile basidia appeared to be less abundant than usual in 

 these specimens. 



Ptychogaster albus, Cord., a Form of a Polyporus.f — This 

 fungus has been variously assigned to the Myxomycetes, Gastero- 

 mycetes, and Hymenomycetes ; and has been considered as a stage of 

 development of another fungus. T. Ludwig has now set the question 

 at rest by the discovery of a second mode of fructification. 



On the entire under side or on free spots of it, it sometimes forms 

 PolyjJorus-tnhes, or the hyph^e display an evident tendency to collect 

 into tubes. Sections through the fungus do not bring out, even under 

 the Microscope, any diiference between this layer and the rest ; both 

 consist of similar hyphfe. The PoZ//porMS tubes are of moderate size 

 with angular or roundish mouth, where they have a few sharp teeth, 

 the extremities of hyphfe which project beyond the mouth. 



On the spots inhabited by the Ptychogctster no other species of 

 Polyporus was found. Ludwig regards it therefore as an independent 

 and new species, most often propagated by conidia and but rarely by 

 the Po?//|>ori<s-fructification, and describes it under the name Polyporus 

 Ptycliog aster. The phenomenon is analogous to that in Fistulina 

 hepatica, in which De Seynes discovered a conidial generation, as did 

 Eidam and Van Tieghem in some species of Coprinus. 



Synchytrium parasitic upon Dryas.| — Dr. F. Thonia,s records 

 the discovery, in the Tyrolean Dolomites, of a parasitic fungus 

 forming galls on the leaves of Dryas odopetala, which he identities 



* ' Bull. Soc. Bot. France,' xxvii. (1880) p. 125. 



t ' Zeitschr. fiir d. Ges. Natur,' 1880, p. 424. See ' Bot. Centralbl.,' i. (1880) 

 p. 865. 



.% ' Bot. Centralbl.,' i. (1880) p. 703. 



