58 DIVISION I.—GENERAL MORPHOLOGY. 
hyphae and of their ramifications appears to be entirely without arrangement. 
R. Hartig’s description of Polyporus fulvus should also be consulted’. - 
Compound sporophores with distinct pseudo-parenchymatous structure ‚could 
only be illustrated by a number of individual cases all differing in many points 
from one another, but such an enumeration would be out of place here. 
One feature common to most, if not all, compound sporophores of all types ot 
structure is the more or less distinct separation of a peripheral layer from the inner tissue. 
Compound sporophores with much internal differentiation, among the Gastromycetes 
especially, exhibit many peculiarities in connection with this point, which will be 
noticed again in later sections in describing individual cases. The separation in 
\compound sporophores with progressive growth, and also in some small ones with only 
slight differentiation, usually consists in the fact that an inner less compact and firm 
mass, which may be termed the medulla or medullary mass, is surrounded in the parts 
which do not directly bear the organs of reproduction, as in the sclerotia, by a 
peripheral rind or cortical layer, in special cases termed also the pelicula or cutts, 
which is the outer boundary of the whole structure. When the compound sporo- 
phore forms organs of reproduction directly on its surface, the hymenial layer takes 
the place of the cortical. Both the medulla and the rind may be separated again 
into subordinate layers. 
The rind is distinguished from the medulla either by the structure, size, and 
firmness of union alone of its elements, their arrangement (the fibrillation) being similar 
in both, or their arrangement also is different. 
In the first case the rind is usually of a firmer texture than the medulla owing to 
the less breadth and closer union of its elements. This is its character in very many 
fleshy or cartilaginous Mushrooms, such as the larger Clavarieae, Calocera, many 
Agaricineae and Pezizeae, and in the stroma of Rhytisma. The cells of the rind have 
also not unfrequently coloured sclerosed walls, which are wantirig in those of the me- 
dulla, as for instance in Peziza hemisphaerica, Rhytisma, Stereum hirsutum, &c. In 
other forms the rind is distinguished from the medulla by gelatinous cell-walls, as in 
the pileus and stipe of Agaricus (Mycena) vulgaris, in the pileus of Russula integra, 
in Panus stypticus, and many other Agaricineae, the outer covering of which is a tough 
gelatinous felt, while the interior tissue is not gelatinous. A different arrangement of the 
elements of the rind from that of the medulla occurs frequently in compound sporophores 
with hyphal structure; the hyphae of the medulla follow in their course the form of the 
sporophore, but numerous curved branches with their convexity towards the apex pass 
off from its hyphae in the direction of the surface, where they terminate in copious 
ramifications and close union with one another. The extremities themselves either 
form a tangled weft, as for instance in Auricularia mesenterica and species of Poly- 
porus, or else they are placed perpendicularly to the surface, so that the rind appears to 
be formed of palisade-like cells or cell-rows, as in Peziza Sclerotiorum, in the large- 
celled tissue of the surface of the stipe of Helvella crispa and H. elastica, in the 
outer and inner surface of the hollow stipe of H. esculenta and Guepinia contorta ?, 
in the smooth surface of the pileus of Polyporus lucidus (Fig. 25), and in that of 
P. fomentarius. 

1 R. Hartig, Zersetzungserscheinungen d. Holzes, p. 40. 
? Dacryomyces contortus, Rabenh. Herb. Mycol. Nr. 1984. 
