222 Prof. G. de Notaris on the Tribe Spheeriacez. 
not now, for want of direct observations, announce the opinion 
T have formed. af 
The perithecia in compound Spherie are found more or less 
deeply inserted into the stroma ; in the simple species they may 
be free or innate, isolated, fasciculate, gregarious or otherwise. 
Their structure deserves the highest attention: the perithecium 
im some species consists of a membranaceous, elastic, transparent, 
reticulated sac, constituted of a smgle stratum of very much com- 
pressed cellules ; in others it is made of minute, round or angular 
cells of varied dimensions, containing a peculiar substance for 
the most part of a fuliginous colour. The consistence, thickness, 
fragility or tenacity depend on the greater or smaller number of 
the cellular elements, which arranged in one or more strata con- 
cur to form the walls, their size and reciprocal cohesion. Some- 
times they consist of an apparently anhistous membrane similar 
to the stratum, which by means of maceration may be separated 
from the epidermis of the leaves of pheenogamous plants. 
If the simple Spherie presented constantly a perithecium of a 
cellular structure, or to speak more correctly, of a stratum of con- 
centric cells, we should think their external coat corresponded to 
the stroma or receptacle which unites the perithecia m the com- 
pound species; but in these as well as the others both forms 
occur. I should rather say that the apparently anhistous peri- 
thecium was analogous to the peridiola of the Mucedines, the 
other to the peridia of some Gastromycetes. 
The Spheriacee, I remark by the way, by the symmetry of 
their parts and their ascigerous fructification, have a great ana- 
logy to the Discomycetes, were it not that the excipulum gene- 
rally speaking has a filamentous instead of a cellular structure. 
The neck of the perithecium, which is highly developed both 
in certain vertical and innate stromatic Spherie, and in simple 
species deeply buried in the matrix, does not furnish characters 
of primary importance. The transitions from Cooperte to Cera- 
tostome are notorious, and from the latter to Platystome, &c. 
The asci and paraphyses, or the asci alone, constitute the nu- 
cleus, the constant property of which in growing individuals is 
to present the character of a gelatine of a whitish, cimereous or 
slightly fuliginous tint. The differences depend essentially on 
the particular state of the asci, and the manner in which the spo- 
ridia of these and the perithecia are set at liberty. When humi- 
dity is wanting, the primary element in the life of Pyrenomycetes, 
the nucleus nearly vanishes, being reduced to a sort of down or 
to a thin crust which lines the base or cavity of the perithecia. 
Nothing can be added respecting the anatomy of the asci, spo- 
ridia and paraphyses which has not already been registered m the 
