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

Smith * Hesler

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In summary, the more important taxonomic macroscopic characters
in Pholiota are color and surface features of the pileus, color of pileus
context, color of the gills and the surface characters of the stipe. The
texture of the inner veil becomes a valuable character when it forms a
persistent, membranous annulus, or leaves copious remnants. Finally, the
color of the inner veil when young is regarded here as of some value in
distinguishing species.
Microscopic Characters
In the present study and in line with the hyphal approach to the
study of the basidiocarp, we have placed emphasis on hyphal end-cells,
whether occurring as pileo- caulo- pleuro- or cheilo- cystidia, the types of
hyphae making up the various tissues, and hyphal detail in the veil in
so far as the available material allowed this. The spores, of course, were
studied on a modern basis with due emphasis on wall features as well as
size and shape. The features offering the most value for taxonomy appear
to us to be spore size, spore shape, presence or absence of pleuro-cystidia
and if present their type, the structure of the pileus cuticle, the presence
or absence of caulocystidia and whether the hyphae of the subhymenium
gelatinize or not.
Spores. We have examined spores mounted in 2% KOH and in Melzer's
reagent when studying dried material. Water and 2% KOH are now both
regularly used on fresh material. The spores under a good oil immersion
lens when viewed individually free from the tissues of the basidiocarp
appear ochraceous to ochraceous tawny, tawny or some shape of pale to
dark cinnamon. Whenever possible spores from deposits were examined;
however for most collections including many of the types, deposits of
spores were not available. Under these circumstances we checked the
spores found on the apex of the stipe while in the process of looking for
caulocystidia. We did not find enough caulohymenium in the species
studied to create a situation similar to that found by bolete investigators
in Leccinum where there is a fairly extensive caulohymenium at times
and the spores produced on its basidia are very different in size and shape
from those on the basidia of the hymenophore.
Spore deposits should be taken on white paper and air-dried or dried
over silica gel before the color is recorded. There is a characteristic range
in color, or color spectrum, for the genus. In this respect Pholiota is like
other large genera such as Psathyrella, Coprinus, Russula, etc. The central
color is a dull rusty brown to cinnamon brown and there are variations
to reddish, earth brown or paler to ochraceous or clay-color to oliveyellow (in P. olivaceodisca). We believe that by using standardized spore
prints by the drying methods suggested here, more can be done with
the color of the spore deposit as a taxonomic character at the infrageneric
level than we have done. We simply do not have the necessary data at this