252 ASCOMYCETES. 



occasional parasite. Schwarz 1 has recently described it as 

 attacking pines, weakened by an impoverished water supply to 

 the twigs and by other unfavourable conditions. It appeared 

 for a time as an epidemic in the pine forests of Germany, but 

 very soon disappeared again. 



The symptoms of disease were, withering of twigs in spring 

 from the apex downwards into the region several years old. 

 The epidemic had been previously noticed in the spring of 

 1892, and was described by Hartig, who, along with Kienitz, 

 regarded it as a result of the long dry preceding winter. The 

 disease has never been observed on pines under five years old, 

 and serious injury only results when the fungus is accompanied 

 by damage done by insects. The apothecia containing the asci 

 are generally produced only on dead twigs and needles. 



Schwarz regards as a conidial form of this species, Brnn- 

 chorstia destruens Erikss., w r hich will be described in greater 

 detail amongst the " Fungi imperfecti." In addition to Brun- 

 chorstia, other pycnidia with unicellular conidia occur. 



DERMATEAE. 



The apothecia, at first spherical and embedded in their host, 

 break out in clumps; they are generally short and thick-stalked, 

 and open to form a roundish saucer-shaped disc with an un- 

 broken rim. The hypothecium is thick and often coloured. 



Dermatella. 



A stroma is developed under the bark of the attacked parts 

 of the host, and in it originate dark brown apothecia with 

 short thick stalks. The bark is ruptured and the apothecia 

 emerge as flat, expanded, saucer-shaped discs with a complete 

 rim. The asci are club-shaped and thick-walled. The spores, 

 at first unicellular, later multicellular, are large and colourless 

 or brownish. The paraphyses are septate and generally forked ; 

 they often form a coloured epithecium. 



Dermatella prunastri (Pers.) (Britain and U.S. America). 

 According to Ludwig, this lives as a parasite on the living 

 bark of plums, apricot, sloe, and other species of Primus* 



1 Schwarz, Die Erkrankung <l. Kief era durch Cenangium abietis, Jena, 1895. 



