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

Smith * Hesler

33

those species with chrysocystidia and related types in "Geophila," but it
must be remembered that the type of Pholiota has these cystidia as well
as lacking gelatinous layers in the pileus cuticle. Consequently we have
adhered to the classical distinction between the two-the color of the
spore deposit-as being the most useful feature and the one leaving us
with the fewest intermediate species.
Pachylepyrium Singer (1957) is to our minds a superfluous genus.
It is admitted that when Singer erected it it seemed quite distinct but in
view of the present study, like Kuehneromyces, it falls by the wayside.
There are a number of species in Pholiota with thick walled (0.5 u/ ~)
spores dark in color-P. pulchella as already mentioned, so this feature
appears in viscid as well as dry species. In fact it is found occasionally
throughout the genus. The character follows about the same pattern of
appearance as thickened cystidial walls, only species with the latter are
concentrated in one section by definition.
The subject of relationships should not be dropped, however, without a few comments concerning Inocybe. Like certain other genera, this
one is an anomaly in that it is readily recognized at sight by the "Inocybe
aspect" and yet when its important macroscopic and microscopic features
are put down on paper the recognition of the genus from the description
is most difficult. If we eliminate the species with angular to nodulose
spores as not presenting a problem, we find the basic features of the
smooth spored species to read very much like those of Pholiota in a number of respects. The color of the spore deposit is not too different (claycolor to yellow-brown or earth-brown); cheilocystidia are practically universally present, pleurocystidia are frequently present, and veil development is copious in a number of species.
The points of difference are that to our knowledge gelatinizing
hyphae in the subhymenium are not found in Inocybe and few if any
species have a viscid pileus caused by the hyphal walls of the epicuticular
lyplIae gelatinizing. Actually, Inocybe is conspicuous among the large
brown-spored genera because of the lack or almost complete lack of the
last mentioned feature. Also, the over-all picture from an ecological standpoint is different. Inocybe like Cortinarius is a conspicuously terrestrial
genus. Pholiota is a conspicuously lignicolous one-so much so that one
retains reservations in his own mind even in regard to species which are
described as terrestrial. The pileus surface is also quite different-in most
Inocybe species it is of dry matted radial fibrils quite different from the
non-viscid Pholiota species. In Inocybe lamprocystidia are common, in
Pholiota they are limited to a single section and may be regarded as
not so clearly differentiated. We do not know of any Inocybe species
with true chrysocystidia. Our over-all impression of the two genera, then,
is that any similarities between them are more likely explained as parallelisms than as indicating close relationship. This conclusion is in line
with that of previous authors and has not been supplanted by the additions to Pholiota included in the present treatise.