CHAPTER III.—SPORES OF FUNGI. 95 
common in the Pyrenomycetes, but further investigation of individual cases is 
desirable. 
The last remark specially applies to a considerable number of Pyrenomycetes, in 
which the asci have the same structure as in Sphaeria Scirpi and S. Lemaneae and 
elongate in the same way if they are placed singly in water when they are mature ; 
among these are Sphaeria inquinans and S. obducens, Schm., Cucurbitaria Laburni, and 
some species of Pleospora!. See Fig. 47. 
In all these species the membrane of the ascus consists of a thin outer layer with 
little power of swelling, and an inner soft gelatinous layer which swells to an unusual 
extent in water. If a ripe ascus is placed in water, the inner layer swells and breaks 
through the outer layer and protrudes in the 
manner described in the case of Sphaeria 
Scirpi. When the ascus is intact the inner 
layer is thin as compared with the cavity 
of the cell and appears to be tightly pressed 
between the unyielding outer layer and the 
protoplasmic utricle, which is tensely filled 
with fluid contents. As soon as the pressure 
upon it is relieved by the bursting of the 
ascus, it swells to such an extent in the 
direction of the longitudinal axis that the 
lumen is contracted into a narrow canal and 
the contents, whether spores or protoplasm, 
are driven out through the fissure. This 
happens in fully developed asci which are 
nearly mature, and in young half-grown asci ; 
in both the membrane in the uninjured state 
is thin as compared with the wide lumen. 
In these species the ejection of the spores 
is rare, though it has been observed ; the asci 
when placed in water swell up at once, even 
after elongation, into a clouded gelatinous 
mass. This may be chiefly due to the fact 
that the asci of these land species which swell 
so readily have always been examined under 
very injurious conditions, in sections, for in- 
stance, or as crushed specimens suddenly 
placed in water, and not in theirnormal state Auch "rn the werithechm weh Coameund plore 
—a treatment which the asci of Sphaeria cellular spores. 5 the same after being placed in water, 
Se R 2 theinner b being and the outer rup d 
Scirpi and S. Lemaneae which grow in water In this specimen the spores were ejected in the same way 
would be better fitted to endure. But the ee ieee sei 
same remark applies also to other asci which 
do not suddenly elongate when isolated in water, as appears from the case of Cordy- 
ceps; these and many others when isolated and immersed in water show more or 
less rapid gelatinous swelling of the walls of the asci. 
Some of the asci of which we are speaking have characteristic thickenings 
on the apical portion of their walls; in Cordyceps, Claviceps, and Epichloe typhina 
the apex is thickened and becomes a nearly cylindrical body, almost as long as 
the breadth of the ascus, pierced longitudinally by a very narrow canal, and set 
like a lid or cork on the thin lateral wall. If we recall to mind the thickened apex 



1 Tulasne, Carpol. 1. c. and II, t. XXVIII,’ &¢.—Currey in Microscop. Journal, Vol. IV, p. 198. 
—Sollmann in Bot. Ztg. 1863: 
