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

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The North American Species of Pholiota

genus. More important, however, is the frequent appearance of chrysocystidia and types approaching chrysocystidia. When Smith (1951) monographed Naematoloma he was not aware that there are more species of
rusty-brown spored agarics with chrysocystidia than there are species of
Naematoloma with purple-brown spores, and hence included some brownspored fungi in Naematolma. These are transferred to subg. Phaeanaemataloma. Some have a truncate spore and some do not. Because of the
number of variations of the chrysocystidial type found in this subgenus,
we believe that this type of cystidium had an independent origin in this
group and that certain aspects concerning cystidial content have been
maintained through the rest of the genus regardless of the morphology
of the cystidium. The development of the apical germ pore of the spore
has occurred in all subgenera, but in Hemipholiota it appears to have
become linked in some measure with the absence of pleurocystidia. Thus
real intergradation with Psilocybe results, since the spore deposit in the
latter genus is vinaceous-brown in some species not too dissimilar from
those of stirps Vernalis.
But Hemipholiota contains a number of evolutionary segments. The
type, P. destruens stands out in the group as an odd-sized species much
as P. ailrea stands out in subg. Flavidula. The P. albivelata group connects obviously to'Stropharia not only by the well developed annulus but
by the presence of chrysocystidia. The spores are not "broadly truncate"
it is true, but neither are they in Stropharia squamosa. In short, from
subg. Hemipholiota as treated here we have the basic group from which
the other subgenera including Phaeonaematoloma most likely evolved.
The major lines of evolution in the genus as we see them, may be
summarized as follows:
1) The development of gelatinous layers-in pileus cuticle and subhymenium-subg. Flammuloides.
2) The development of the outer veil to form dry scales as it breaks on
both pileus and stipe-subg. Pholiota (type species).
3) The development of "dry" species either with a granulose outer
covering (veil) or trichodermium as a pileus cuticle in the extreme
forms-subg. Flavidula.
4) A development leading toward Stropharia, Naematoloma and Psilocybe (the "Geophilia" group). This we distinguish as a separate taxon
because the features of a truncate spore and presence of chrysocystidia
become linked in Pholiota to make a unified group distinct from
Hemipholiota. The interesting feature here is that in reality these
two features are not any more closely linked in the "Geophila" group
than in Pholiota. In Geophila we have purple brown-spored fungi most
of which have more or less truncate spores, and many of which have
chrysocystidia. In fact, with the present study as a background, it is
now clear to us that if Pholiota is to be maintained as distinct from
"Geophila" the color of the spore deposit makes a better distinction