688 
Beer.—Notes on the Development of the 
Summary. 
A. Hypholoma fascicularis (Huds.). 
1. The very young carpophore consists of a mass of densely interwoven 
hyphae enveloped in a layer of looser hyphae. 
2. The first differentiation of parts in this carpophore consists in the 
appearance of a cup-shaped layer of'deeply staining hyphae a little way 
below the surface at the upper end of the young fruit-body. This marks 
the primordium of the pileus, which is thus the first part to differentiate in 
Hypholoma . 
3. The inward extension of the edge of this cup defines the hymenial 
layer. 
4. Below this primordium of the hymenium an air-space—the gill 
cavity—-is formed. A marginal veil can now be clearly distinguished. It 
is derived from the neutral tissue just outside and below the hymenial layer; 
it is present from the first and is not an aftergrowth. 
5. The stipe differentiates into a cortical and a medullary region. It 
later becomes hollow. 
B. Clitocybe laccatns if) cop.). 
6. In this plant also the first differentiation of the carpophore consists 
in the demarcation of the pileus. It appears as a cup-shaped layer of hyphae 
lying a little way below the surface at the upper end of the elongated carpo¬ 
phore primordium. 
7. The rim or edge of the ‘ cup 3 grows inward to form the rudiment of 
the hymenial layer. 
8. A poorly-developed universal veil surrounds the whole carpophore 
at first. At an early stage, however, the lateral growth of the pileus rup¬ 
tures this universal veil, and the whole of the rest of the development of 
the hymenium takes place whilst this is exposed to the air and unprotected 
by either a marginal or universal veil. 
C. Armillaria mellea (Vahl.). 
9. The primordium of the hymenium is the first part to become 
differentiated in the plants which I have examined. It has an endogenous 
origin. 
10. The pileus becomes differentiated soon after the hymenium has 
been marked off. 
11. The hymenium is never exposed in an open furrow. On the con¬ 
trary, the marginal veil is present from the first, and is never an aftergrowth 
as Hartig supposed. 
