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

Smith * Hesler

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in this group that it appears that we are dealing with a group in which
chrysocystidia are originating, and that various stages of development will
be encountered, depending on which chemicals or stains one uses to
differentiate the physical properties of the cell content.
We have also found that while the morphological types already outlined are in the main distinct, there are many species in which intergradation between types occur. In P. simulans, for instance, the pleurocystidia
(as chrysocystidia) measure up to 58 p/ long-as long as for many of the
Flammuloides-type and are fusoid-pointed. To this one can add other
information such as that in a number of the characteristically chrysocystidiate species such as P. prolixa, the amorphous-refractive inclusion becomes red in Melzer's reagent, indicating a chemical difference in the
material involved when compared with species in which the chrysocystidial inclusion is merely dingy yellowish to scarcely colored in
Melzer's. In P. aurea some of the basidioles, as revived in KOH, have an
amorphous content resembling that of true chrysocystidia.
In our estimation one of the most interesting features discovered in
the course of the present study is that cystidial shape and content are not
necessarily correlated, and that the characterization of "chrysocystidia
present" is hopelessly inadequate by itself in describing the cystidia of a
Pholiota. A major feature of Pholiota is the diversity in cystidial content
-as indicated in our descriptions. It deserves a special study by microchemical tests. It is hopeless to try and limit the term chrysocystidia in
this genus to the end-cells of the hyphae of the laticiferous system as
these occur in the hymenium. In P. sola we have observed hyphae with
the content of oleiferous hyphae which ended in basidia with spores
attached and with the basidia having the same distinctive content as the
hyphae from which they originated. In short, Pholiota is a most interesting genus from the standpoint of the content of the hyphal cells.
The absence of pleurocystidia is the most difficult feature to use,
since one must first search for imbedded cystidia, but there appears to be
a group of species in which hymenial cystidia are truly absent. For this
group it is actually best to check dried material because it is rather easy
to spot the refractive inclusion in the hymenium of a chrysocystidium
before one makes out the outline of the cell around it.
Cheilocystidia. By definition these are the hyphal end-cells on the
gill edge which do not produce basidiospores. They may be in the form
of basidioles, resemble the pleurocystidia in shape, or have their own
distinctive morphological characters. They may also have distinctive
content in the form of amorphous refractive material or a dull brown
homogeneous content. In the subgenus Pholiota in some species the
chrysocystidia found as pleurocystidia can also be found in the hymenium
covering the gill edge. This is by no means unexpected. The same can
be said for the types of pleurocystidia which approach in some measure
true chrysocystidia. If fertile basidia occur on the gill edge these types are
also to be expected there. In subgenus Flammuloides the cheilocystidia