506 Fischer .—On the Development of the Fructification of 
The pileus assumes a globular shape by continued growth, still further 
separating the hymenium from the ‘ neutral tissue which increases the 
depth of the gill cavity (Fig. 8). 
The size of the sporophores does not necessarily correspond with the 
degree of development, so that it is not possible to indicate the stages 
of growth by external description. This will be seen by comparing Figs. 5 
and 6 , both drawn to the same scale, 5 being the younger stage. 
Soon after the last described stage the lower portion of the pileus 
begins to grow out and upwards, stretching the neutral tissue to which it is 
still attached by its margin (Fig. 8). 
By this time the universal veil has entirely disappeared, as also the 
loose lacunar tissue which surrounded the stipe and was previously covered 
by the veil. It is at this stage that the mucilaginous coating begins to 
appear on the surface of the pileus. 
The neutral tissue is much drawn out by the outward growth of the 
pileus, and becomes very loose and almost diaphanous by the separation of 
its elements. This is the velum partiale. Sooner or later it is ruptured at 
the edge of the pileus, sometimes not till the latter is nearly horizontal, 
remaining attached to the stipe as the annulus superus. 
During this last period of development the hymenial layer differ- 
entiates its elements of basidia, paraphyses, and cystidia. The spores are 
formed before the rupture of the veil, and I found them capable of germina- 
tion even when the veil had to be pierced to obtain them. 
The mucilage of the pileus is derived from the disintegration of the 
extremity of the palisade layer laid bare by the disappearance of the 
universal veil, the remainder of the palisade layer persisting. That the 
mucilage is due to decomposition and is not merely a secretion is evidenced 
by the particles and rounded cells found embedded in it (Fig. 9). The 
mucilage gave an acid reaction with litmus paper. 
Summarized, the results are as follows : — 
I. A universal veil exists which disintegrates after the differentiation 
into primordial stipe, pileus, and hymenium. 
II. The origin of the hymenium is endogenous. 
III. There is no separation of pileus and stipe by the formation of an 
annular air-space. 
IV. The marginal veil ( velum partiale ) Is not an aftergrowth , but 
is formed by the neutral tissue, which is present from the beginning. 
V. The mucilaginous coating of the pileus is derived from the de- 
generation of the apical portion of the palisade tissue. 
An early examination of the very young stages of the sporophores of 
Armillaria mellea seems called for. This species is readily cultivat 
in the laboratory (see Brefeld’s ‘ Untersuchungen aus dem Gesamtgebic 
