138 
THE DICTIONARY OF GARDENING, 
Pinus—continued. 
Fia. 164. Trametes Pint, showing (p) Pileus and (£) Openings of i 
Spore-bearing Tubes. 
form of Red Rot. It is often the cause of injury to 
forests on the Continent; but it is too rare in Britain to 
give occasion for alarm. 
, b, Bark of Fir-tree. 
Fie. 165. AGARICUS MELLEUS, showing, at the base, Mycelium of 
the Form called Rhizomorpha fragilis—h, Annulus, or Ring; 
9, Gills ; p, Pileus. 
Agaricus melleus (see Fig. 165) very much resembles 
Polyporus annosus in its effects upon the trees which it 
attacks; but it is far less particular as to its host, not 
by any means confining itself to Conifers. It is one of 
the Mushroom group of Hymenomycetes, with the spores 
produced on gills on the lower surface of the pileus. 
The latter part is convex above and varies from honey- 
colour to brownish, with blackish scales upon it. The 
pileus, or cap, varies from 2in. to 7in. in breadth. The 
caps spring up in large clusters, near the roots of trees, 
or on them, or low on the trunk (see Figs. 166 and 167). 
On tracing the mycelium, it will be found growing between 
the wood and the bark, in black, string-like or flattened 
bands, called Rhizomorpha subcorticalis and R. fragilis, 
which were formerly regarded as distinct and independent 
Pinus-—continued. 
species (see Figs. 168 and 169). Other Agaries also are 
parasites, but none are equally dangerous with A. melleus. 
Another Fungus injurious to Fir-trees is Peridermiwm 
Pini, which occurs upon both branches and leaves. The 
branches are generally destroyed by it, the leaves 
do not show signs of serious injury. 
mium. 
See Perider- 
Fic. 166. MASS OF AGARICUS MELLEUS ON ROOT OF YOUNG PINE 
—a, a, a, Mycelium in form known as Rhizomorpha fragilis ; 
b, Very young Spore-bearers produced on Rhizomorpha fragilis ; 
d, Older Spore-bearers (Agaricus melleus) produced by Myce- 
lium of form known as Rhizomorpha subcorticalis. 
The needles on various Conifers, in many parts of 
the country, are very frequently studded with one or 
more rows of small black bodies, which, under closer 
examination with a lens, are found to have a slit running 
from end to end of the upper surface. These are the 
perithecia of several species of Fungi grouped together 
in a genus called Hysterium. That on the Scotch Fir 
is H. pinastri. It is hurtful by causing the premature 
fall of the needles, and a consequent loss of nourishment 
tis. 
Fic. 167. AGARICUS MELLEUS. Group of young Spore-bearers (e) 
produced on Rhizomorpha subcorticalis (a), which is also shown 
spreading upwards at d; b, Sterile Mycelium in form 
izomorpha fragilis. 
to the trees. 
latively large cells (asci), inclosing eight long, slender, 
colourless spores. The tissues of the needles are early 
traversed by the mycelium of the Fungus; and the 
needles fall off usually at the end of their first year 
of life, but the Fungus is matured only after the leaves 
have been lying on the ground for some time. 
It must be borne in mind that unhealthy external con- 
ditions, such as sterile soil, bad drainage, or lack of free 
In each perithecium are numerous re- 
