550 
^lE. F. CUEEET ON THE FEUCTIFICATION 
produced upon the same mycelium ; but other cases occur in which the normal form of 
fruit is so far modified and altered by external cii’cumstances, as to appear at first sight 
as if belonging to a different species or even genus. 
It is an opinion rapidly gaining ground, that by far the greater number of the plants 
composing the genera Diplodia, Sporocadus, Sphceropsis, Hendersonia, Phoma and others, 
are only imperfect forms of different species of Sphaeria, and a wide field of observa- 
tion is thus opened in order to allot to each individual member of these pseudo-genera 
its proper place in the mycological system. 
The following instances of this change of form in the fruit have come under my own 
observation : — 
1. Sphceria angulata^ Fr. — T his Spheeria is very common, being found upon almost 
eveiy small dead fallen branch of Oak. It belongs to the division Incusse, the perithecia 
being imbedded in a stroma formed from the bark in small circular patches. The peii- 
thecia, with the exception of the ostiola, are usually completely hidden by the bark ; but 
the space which they occupy beneath it is generally well defined by a circular mai’k 
surrounding the base of the broad-angled cone, into which the bark is raised by the 
growth of the ostiola. The sporidia are oblong, but constricted in the middle, var^fing 
in length from to s^-g-th of an inch, and having a septum at the constriction. 
They are colourless, and their appearance varies considerably according to the state in 
which the endochrome happens to be at the time of observation. This difierence in 
the endochrome will be seen by referring to figs. 20, 21 and 22, Plate XXV. ; in the 
former the endochrome has a clear oleaginous nucleate appearance, and fills each cell of 
the sporidium, leaving how^ever a manifest interval between it and the outer membrane ; 
in figs. 21 and 22, on the other hand (the latter representing free sporidia), the endo- 
chrome is broken up into a granular mass, which fiUs each cell of the sporidium so 
completely as to render the outline of the outer membrane no longer distinguishable. 
I may observe that this change of state in the endochrome, although striking at first 
sight, is not uncommon in the sporidia of Sphserise, and it is a circumstance which 
must always be carefully attended to when the form and structure of the sporidia are 
resorted to for distinguishing species. In this instance the ^difference between what 
may be called the nucleate and the granular sporidia is so great, that they might at 
first sight be supposed to be different forms. In fig. 20 {a) is magnified 315 and [h) 
415 diameters. Figs. 21 and 22 are magnified 315 diameters. 
There is another peculiarity connected "svith this Sphceria, which is, the existence in 
all i\\e free sporidia of four delicate cilia, one proceeding from each pole, and one fi'om 
each side, which are not perceptible as long as the sporidia are enclosed in the ascus. 
The fact of these cilia being invisible in the ascus might seem to point to germination 
as their origin, but the constancy and regularity in their appearance, size and position 
almost preclude this supposition. 
The above varieties in the sporidia are not, however, the main peculiarity in the 
fructification of this Sphreria, for I have found its perithecia producing in lieu of the 
