528 
W. H. SAWYER, JR. 
representing two other Friesian subgenera. No generalizations can 
be made until the development of many more species is known, but 
the evidence at hand indicates that the presence of a universal veil 
(blematogen) is constant for the genus. If so, it is probable that it 
plays some part in the origin of the cortina, as in the species studied 
by Miss Douglas, and as it does in this species. 
In conclusion, I wish to acknowledge my indebtedness to Professor 
George F. Atkinson, under whose direction the greater part of this 
work was done at Cornell University, for his helpful interest and 
kindly criticism. 
Summary 
1. The primordium of the basidiocarp of Cortinarius pholideus is 
composed of slender hyphae interwoven into a compact structure 
with numerous interhyphal spaces, and enveloped in a layer of dif- 
ferentiated hyphae. 
2. These enveloping, radiating hyphae form the blematogen or 
universal veil. They are loose in their arrangement, with large, 
thick-walled cells. Soon after pileus formation the blematogen shows 
a double character over the pileus margin and gill cavity. The inner 
layer has an upward growth direction and the hyphae of the pileus 
surface interlock with its upper portion. 
3. The appearance of the stem fundament is the first differentiation 
to take place within the basidiocarp. It is formed in the base of the 
fruit-body, and advances to the apex by progressive growth and dif- 
ferentiation. 
4. The pileus is formed by the expansion of the stem apex, due to 
interstitial and divergent growth. The lateral hyphae of the pileus 
fundament by epinastic growth form the pileus margin. 
5. Perpendicular downward growth of hyphae from the under 
surface of the pileus, beginning in the angle between stem and pileus, 
forms the primordium of the hymenophore as an annular zone of new 
growth surrounding the stem apex. At first, because of unequal 
growth of its hyphae, the primordium is uneven and jagged, but later 
the ends of the hyphae grow down to the same level, forming the even 
palisade zone. 
6. The annular prelamellar cavity is formed by the breaking away 
of ground tissue left in the angle between stem and pileus after their 
differentiation, due to the growth and expansion of these parts. A 
small amount of this ground tissue may remain attached to the edge 
of the pileus and form a slight element of the cortina. 
