50 
TWO NEW BASIDIOMYCETES. 
By H. Bourdot. 
Among the interesting species which Mr A. A. Pearson has 
been kind enough to send me, are two which have not yet 
been described. One of them has been gathered several times 
in France by M. A. Galzin, and it may be that the species are 
not very rare; but they are so delicate in substance and dis- 
appear so quickly that few observers in the field have paid any 
attention to them. 
One ought perhaps to mention that besides the difficulty of 
recognising these minute species, there must be considerable 
hesitation in recording them as new. The reason for this is 
that certain Basidiomycetes are fertile at a very early or larval 
stage when they present a very different appearance from the 
fully developed plant. 
Cortictum rubropallens (Schw.), C. lividum Pers. etc. form at 
first a pruinose film barely visible; the basidia which are already 
fertile grow in tufts on the few mycelial hyphae that are 
scattered over the substratum. In the case of such species, the 
microscopic characters are practically the same as in the adult 
stage, and usually one is given a clue to their identity by parts 
of the sporophore which, especially towards the centre, are 
more developed and more normal. 
In other cases, Stereum purpureum Pers., S. Karsteni Bres., 
Contophorella olivacea (Fr.) Karst., the early form is more dis- 
tinct, and the cystidia especially are so profoundly modified 
that identification is only possible if one follows for some time 
the development of the fungus. Some Stereums may start in 
two ways: in the form of tubercules, small discs or patches 
with well-defined edges; or in a diffused form, which remains 
for some time hypochnoid or corticioid. This last mode of de- 
velopment is fairly frequent in Stereum purpureum, and one can 
easily observe it on trunks or branches of poplar which remain 
some years on the ground, or in the timber yard. Towards the 
end of the summer the fungus forms a rather light pruinose 
film, which is already fertile and gradually acquires first a 
pellicular then a membranous, pale yellow hymenium. The 
microscopic structure is then almost exactly that of Peniophora 
sublaevis Bres. and at this stage of development the vesiculose 
cystidia characteristic of Stereum purpureum are either com- 
pletely absent, or very rare. There are, however, numerous 
hymenial cystidia which are slenderly fusiform, of the same 
