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

Smith ~ Hesler

23

species in subg. Flammuloides the hyphae at the stipe apex darken
strongly in KOH. This is a feature of some significance, especially in the
study of dried specimens.
Caulocystidia. In all Pholiota material examined in this work, longitudinal sections of the stipe apex (between the pileus and the annular
zone) have been prepared and have been examined for caulocystidia. In
many species caulocystidia were absent; in many others they were present
and readily found. In instances where present, their morphology, is one
of two types: 1) those which were similar to the cheilocystidia (or even
the pleurocystidia, if present); and 2) those which differed in shape from
the lamellar cystidia. In general, they may be scattered along the surface,
or, in some species, may occur in distinct clusters or rosettes.
The taxonomic value of caulocystidia is, in our view, somewhat uncertain. In some collections of a species, they were found; in other collections of the same species they appeared to be absent. This situation was
encountered sufficiently in these studies to cause avoidance of any considerable use of these structures in the separation of species or larger
entities. Further study of their occurrence is necessary to a clear understanding of their significance in Pholiota systematics, but studies should
be based on fresh material. Large thin-walled vesiculose cells in particular
are often difficult to revive.
Clamp connections. For practical purposes, clamp connections were
found in all species of Pholiota studied (except for P. fulvosquamosa and
P. cinchonensis). In rare instances, we assume that they escaped detection, either because they were very small and inconspicuous, or they were
indeed very rare in their occurrence. We are not yet ready to assume that
when not found in the course of ordinary examination they are not
present to some extent somewhere in the basidiocarp. Because of their
(almost?) universal presence in Pholiota, they offer no help in the
separation of taxa, a situation in contrast to that in the genus Crepidotus.
Chemical Characters
KOH was used as a standard mounting medium and the usual darkening of hyphal walls from ochraceous to rusty brown was noted as
occurring but has not been given particular emphasis in infrageneric
classification simply because it did not seem practical. No red or green
reactions as one frequently finds in other genera-Panus, Cortinarius,
etc. were noted. KOH on the fresh basidiocarp usually gave some degree
of browning reaction, but more studies are needed here as our data are
necessarily incomplete, though the KOH reactions are apt to be at least
somewhat similar on both fresh and dried material. KOH often dissolves
the yellow to brown pigment to some extent. This is readily observed in
the mounting medium.
FeSO4 has been tested to some extent, mostly in recent years, and