Prof. G. de Notaris on the Tribe Spbseriaceae. 221 



it is preceded by tlie appearance of the perithecia. In many of 

 the Obvallata, Pertusce, Denudata, Caulicola, and analogous tribes 

 of Fries^ the matrix at first appears unaffected ; neither do we see 

 it penetrated by the stromatic substance, if it has not abeady 

 completed the development of the perithecia ; for which reason I 

 should feel inclined to regard this indeterminate form of stroma 

 either as the result of a peculiar disorganization induced in the 

 substance of the matrix from the corroding action of the concep- 

 tacula as the rudiments of abortive perithecia, or in short as a 

 sort of secretion from the conceptacula themselves which filters 

 through the pores of the matrix, or is diffused on their surface 

 and by degrees vanishes. 



This latter mode in which the stromatic substance originates 

 is a fact repeated in a multitude of species, and which has to a 

 certain extent some analogy with the changes effected in the more 

 superficial strata of the bark in woody dicotyledonous plants, in 

 which the external cells of the cortical parenchyma have not be- 

 come inert and modified in their qualities and appearance by the 

 continual action of atmospheric agents, though certainly by the 

 progressive deposit of the superfluous nutritive particles. 



However this may be, I refer to the Simplices all those species 

 of the first division of Fries in which the stroma has no deter- 

 mined and constant figure nor free evolution, in consequence of 

 which I unite, according to their real afiinities, many forms which 

 till now have been ascribed to separate sections ; for example, 

 Spharia leioplaca and S. miliaria of the Concrescentes to S. en- 

 typa and S. inquilina of the Obtectce. And why may we not be- 

 lieve, from the great similarity of the simple species to certain 

 VerrucaricB, that we shall be able to clear up the same aberrations 

 in the Sphcerice which so often recur among the lichens with a 

 centrifugal thallus, in which we find apothecia developed inde- 

 pendently of the thallus ? I must however add, that I have never 

 met with isolated independent perithecia of the same form as 

 those in any of the stromatic or compound species. Besides, the 

 differences of the sporidia in the species of the types just indi- 

 cated are adjusted ; differences, which when clearly expressed may 

 be assumed as the fundamental hinge of the primary divisions 

 analogous to those adopted by Fries. 



In the works of the above-mentioned authors, the particulars 

 relative to the configuration of the stroma are minutely described ; 

 it therefore appears to me superfluous to say more about it. 

 Many, on the contrary, would like to discourse about the nature, 

 use, and signification of the tomentose subiculum with which the 

 perithecia are girt in the Byssisedce and various other sections. 

 This structure does not necessarily indicate affinity ; but I dare 



