58 
leaf, in December. Owing to the fact that it is always found associated 
with Gloco&porium nerviscquum and in its immediate vicinity, it is sus¬ 
pected that the two are stages in the development of the same fungus, 
the more so because the spores are so very similar. It is conceivable 
that the mycelium passes from the petioles into the branches and 
there produces the pycnidia of JHscula whose spores develop into Gloco- 
s'porium upon the leaves.* But such a connection could not be estab¬ 
lished either by natural or artificial methods, and the question still 
remains an open one. 
(To be continued.) 
NORTH AMERICAN AGARICS. 
(Genus Russula (russulas , reddish). Fr. Hyra. Eur., p. 430.) 
By Robert K. Macadam. 
Part I. 
Pileus flesliy, convex then expanded, and at length depressed; stem 
stout , polished, not corticate , generally spongy within, confluent with the 
hymenophore ; gills nearly equal , milJdess , rigid , brittle , with an acute 
edge, sometimes dropping water ; trama vesiculose ; veil entirely obso¬ 
lete ; spores white or very pale yellow, generally echinulate. 
Habitat. —On the ground, generally in woods or the vicinity of trees 
in summer and autumn. 
This genus is interesting on account of the beauty and brilliant col¬ 
oring of many of its species, and especially so to amateurs, as it is one 
of the few divisions of Agaricini which can be readily distinguished. 
Members of it may be recognized by the stout spongy stem, dry texture, 
and extreme brittleness; they are generally found in grassy woods and 
are of nearly all colors, frequently with the cap a brilliant red, pure 
white, or white blotched or shaded with red. Russula is allied to Lac- 
tarius , but is distinctly separated by the absence of milk in the gills ; 
those of some Russulw distill drops of water, especially in rainy weather. 
The internal structure is also related, as shown by the presence, in the 
acrid species, of the milk-secreting vessels of Lactarius , but in an unde¬ 
veloped form. 
* At the bases of the infected shoots this spring there was almost invariably a dead 
area on the lignified branch, and mycelium was invariably present ifl the tissues; 
this mycelium penetrated into the vessels of the wood and could not be morpholog¬ 
ically distinguished from that in leaves infested with G. nerviscquum. Many buds 
had died either in late autumn or during winter and there were similar but larger 
dead areas around them, and in these Discula platani often made its appearance. 
Indeed, it is almost impossible to avoid the conclusion that the mycelium of Glocospo- 
rium nerviscqu um extends into the woody parts of the branches, where the fruit of the 
fungus .assumes a different form. The formation of the mass of pseudo-parenchyma 
may possibly be explained on the ground that it is necessary in order to rupture the 
epidermis and cork layer of the bark ; and when this is accomplished it disappears.— 
E. A. S. 
