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

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The North American Species of Pholiota

the general tendency to produce a rather persistent yellow pigment with
the result that color throughout the subgenus falls rather strikingly into
a spectrum from pale yellow to rich reddish brown. Since this is also a
feature of the subgenus Flammuloides and subg. Pholiota, (the bulk of the
genus), we believe the pigmentation pattern supports our conclusions in
regard to the probable path of evolution as based on the structure of the
pileus cuticle. Hence we have used Romagnesi's admirably descriptive
name, Flavidula, for this group.
To us it is also an indication of a connection to Pholiota that P.
corticola and P. cyathicola have a gelantinous subhymenium-a very
prominent feature in subgenera Flammuloides and Pholiota.
We have found pleurocystidia present as pseudocystidia on P. murrillii, leptocystidia in P. erinacea, P. pseudolimulata, P. corticola P.
cyathicola, P. anomala, and P. canescens-the latter two not typical of
the central group in Phaeomarasmius. To us, however, this means that in
this group as in most groups of Agaricales, some species do develop cystidia
and that as a character it does not correlate with the other features of
Phaeomarasmiuls.
Because the problem of Phaeomarasmius (type species), Tubaria
and certain other brown-spored agarics with small basidiocarps needs to
be made the object of a special study involving E.M. photographs of
spores, our purpose here is to merely group in Pholiota the species we
suspect belong there in a natural classification and obviously do not
claim to have investigated all ramifications of the problem of the borderline taxa. Phaeomarasmius is thus maintained at least temporarily for
the species with eccentric stipes or lateral attachment of the pileus to the
substratum.
Kuehneromyces. This genus was proposed by Singer and Smith
(1946) for Pholiota species with truncate spores. In the course of the
present study this feature came under critical scrutiny with some interesting results. In P. minutula of subg. Flavidula we found that with a 1.4
N.A. oil immer. lens the larger spores appeared truncate. In a number of
specimens of Pholiota aurivelloides the spores, or at least many of them,
appeared truncate. It will be noted in the descriptions that for many
species the germ pore is large enough to affect to some degree the configuration of the spore apex. To this one might add that by far the
majority of species included in our concept of Pholiota have spores with
an apical pore. The unavoidable question, then, is not one of the presence or absence of a pore, but rather how large it is-and it is here that
the main character for Kuehneromyces as a genus breaks down. For the
spore in most of the species included by Singer (1963) is not "always
with a broad truncate germ pore" (I.c., p. 549). We even noted one
instance of a basidiocarp with two and four-spored basidia where the
large spores were truncate but those on four-spored basidia were not.
Singer attempted to correlate the truncate spore with other features such