The North American species of Pholiota, by Alexander H. Smith and L. R. Hesler.

18

The North American Species of Pholiota

priate for this type as a name since the type species of Flammula does
not have pleurocystidia. In shape this type is basically fusoid-ventricose.
There is a long narrow pedicel, a broad submedial enlargement and a
long often tapered neck ending in an obtuse to subacute apex. In many
species the wall is uniformly rather thin, but in some the wall is obviously
thickened at least over the ventricose region. In the following account
the dividing line between "thick" and "thin" is at 0.5 Fu. In some species
less than half the cystidia will show a thickened wall. In others nearly
all the cystidia will have walls 1.5-3 pu thick. There is an interesting
problem here in the nature of the cell wall which needs critical study.
We have used this wall feature as a sectional character in Flammuloides
in order to focus attention upon it.
In some species the neck is more or less of equal diameter but in
others it tapers gradually outward to the apex. In P. macrocystis the neck
is rather uniformly constricted at its base. The apex, in a few species, may
be encrusted and varies from acute to obtuse or broadly rounded. The
content of these cystidia is of some interest. As revived in KOH many
are found to have a homogeneous plug of yellow material which more
or less fills the neck and may fill or nearly fill the ventricose portion also.
Since chrysocystidia are described by some authors as having a yellow
content in ammonia, or becoming differently colored with other dyes,
the question as to whether these large cystidia are leptocystidia (which
are said to lack distinctive content), or gloeocystidia of the type called
chrysocystidia, is worth some thought. A discussion of this point is included under chrysocystidia. We have used the presence of these large
pleurocystidia as the major feature of subgenus Flammuloides.
2. Chrysocystidia. In subgenus Hemipholiota as well as in section
Pholiota, pleurocystidia of a kind different from the Flammuloides type
are encountered. In general, these are non-projecting, clavate, often with
an apical short protuberance, and often with an amorphous yellowish
content in the enlarged portion as revived in weak bases such as KOH.
Not infrequently the amorphous content is present only in some of the
cystidia as seen in a given gill section, the others having a hyaline homogeneous content. This type of pleurocystidium (with the amorphous content) is termed a chrysocystidium if it has the refractive content or inclusion as revived in KOH. Their presence is used here as one of the
features for distinguishing subgenus Pholiota. Accompanying these, one
also often encounters pleurocystidia which are more or less clavate and
at the same level as the basidia in the hymenium, but in contrast to the
true chrysocystidia, their contents are partially or wholly brown. Since
all these types of buried to very slightly projecting pleurocystidia are of
about the same type and size, they have here been used to group together
the species showing them. It should be understood that we recognize this
collection of sterile end-cells as colored basidioles, true chrysocystidia and
small leptocystidia, but in this group they intergrade to a remarkable
extent. The point in our plan, which has some significance, is that it is