Prof. G. de Notaris on the Tribe Spheriacez. 221 
it is preceded by the appearance of the perithecia. In many of 
the Obvallate, Pertuse, Denudate, Caulicole, 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 already 
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 tepeated 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 affinities, many forms which 
till now have been ascribed to separate sections ; for example, 
Spheria leioplaca and S. miliaria of the Concrescentes to S. en- 
typa and S. imquilina of the Obtecte. And why may we not be- 
lieve, from the great similarity of the simple species to certain 
Verrucarie, that we shall be able to clear up the same aberrations 
in the Spherie 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 Byssisede and various other sections. 
This structure does not necessarily indicate affinity ; but I dare 
