220 Prof. G. de Notavis on the Tribe Sph^riacese/ 



the genus Sphcsria, proposing the genera Diplodia, Ostropa, Cu^ 

 curbitaria, Cryptosphceria, Vaisa and Hypocreaj which conve- 

 niently hmited according to the characters of fructification com- 

 mon to the greater number of the respective species, and selected 

 from the heterogeneous materials which they everywhere con- 

 tain, ought without doubt in some measure to be adopted, 

 although for the most part founded on the appearance of the 

 stroma, perithecia and nucleus, characters comparatively of small 

 value. 



I comprehend among the Pyrenomycetes Sphceriacea, those 

 species only in which we meet with truly ascigerous conceptacula 

 or perithecia, whether spheroidal, lentiform, conical, oval ; whe- 

 ther obtuse or acute, or finally produced into a kind of cylin- 

 drical neck, angular or compressed, isolated or gregarious, or 

 collected together in a stroma of varied form ; opening by means 

 of a vertical pore, sometimes scarcely visible or gaping in conse- 

 quence of the thinness of the exterior coat, which yields readily 

 to the shock of the sporidia bursting forth from the asci when 

 arrived at maturity, or of the asci themselves separated from the 

 walls of the perithecia, or in short by means of an irregular 

 fissure. 



The limits indeed within which the celebrated Corda has cir- 

 cumscribed the tribe or family of the Sphariacea, in his immense 

 iconographical work on the family of Fungi (Icones Fungorum, 

 vol. V. p. 31), might be adopted for the present, had he not as I 

 believe comprised in it genera which do not properly belong to it, 

 and for the most part defined too loosely. 



In the Sphceriacece we have to consider the stroma, the peri- 

 thecium, its texture, the mode in which it opens, the nucleus, the 

 asci, the paraphyses and the sporidia. 



The stroma, on which the fundamental divisions of Fries are 

 based, furnishes characters of some importance in the greater part 

 of compound Sphcerice, which, besides serving as a receptacle for 

 the perithecia, presents a determined form characteristic of each 

 species. The stroma cannot properly be compared to the thallus 

 of Lichens, because it is an integral part of the fructifying appa- 

 ratus. From the mycelium, the true equivalent of the thallus, 

 one can scarcely draw materials for the diagnosis of the genera, 

 because it is always extremely difficult to follow up its develop- 

 ment. Deeply invested in the substance of the matrix or con- 

 fluent with it, and often evanescent in fructifying individuals, it 

 cannot afibrd precise characters except by the help of observa- 

 tions, often perhaps impracticable, and attentively following up 

 the development before the evolution of the perithecia. In the 

 simple, free, superficial or innate species, and in the Ccespititia, the 

 nature of the stroma appears less clear, because in some species 



