THE DEVELOPMENT OF CORTINARIUS PHOLIDEUS 
W. H. Sawyer, Jr. 
Introduc'iion. 
Cortinarius pholideus is characterized by the pecuHarly strong 
development of dark, pointed, erect scales on the pileus and stem. 
This feature is unusual in Cortinarius, but is very striking in certain 
species of Pholiota, so that Cortinarius pholideus in its general aspects 
suggests Pholiota, the spore color in the two genera being the same. 
Since I have recently studied three scaly species of Pholiota (12), it 
therefore occurred to me that it would be extremely interesting to 
study the development of this species, which I found in all stages of 
development in the same region in which the Pholiotas^ were collected. 
Especially would it be interesting to determine the formation of a 
cortina in a species where such a prominent, coarse, universal veil is 
present. 
Primordium of the Basidiocarp 
The very young fruit-body is elongate, composed of slender, 
closely interwoven hyphae, with numerous interhyphal spaces. These 
hyphae are, in general, parallel with the long axis of the basidiocarp; 
they have abundant protoplasm and are active in growth, as indicated 
by their deeply staining property and long slender cells. The periph- 
eral threads, however, take the stain poorly or not at all. They 
turn outward on all sides, and in an extremely early stage the outer- 
most cells are enlarged, dead, and brown in color. 
This outer zone of differentiated hyphae forms a loose-meshed 
envelope for the entire plant, and is a universal veil, or blematogen, in 
the sense in which this structure has been interpreted by Atkinson (4). 
Figure i represents a median longitudinal section through a very 
young fruit-body, which is about one millimeter long and half a 
millimeter in width. The hyphae are slender and very uniform in 
size, averaging about 2, jJi in diameter. The loose peripheral threads 
belonging to the blematogen, however, are enlarged, many of them 
being 10 /x in diameter, dead, and brown. A conspicuous feature of 
^ Woods in vicinity of Seventh Lake, Adirondacks, N. Y. 
520 
