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

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The North American Species of Pholiota

The lack of macroscopic data on most of the herbarium material we
have studied prevents accurate identification of it. The problem here,
however, is that of the group as a whole. In order to focus on the features
of importance in the recognition of species one first must study the group
to ascertain what characters are present, and if possible obtain data on
their variability. The only way this can be done scientifically is to set up
a classification as we have done here and use it as a testing mechanism
with reference to further field studies and studies in culture. The time
to pass judgement on the species concepts is after the data have been
accumulated and studied, not before, as has been done all too frequently
in the past.
We have evidence that the same problem of variants within this
complex is present in Europe as well as in North America. A collection
by Romell (no. 9782) is an example. lTle following are our data on it:
Spores 6-7.5 (8) X 4-4.5,u, smooth, apical pore minute and inconspictuous (tinder oil); shape in face view elliptic to oblong, in profile
very ol)scurely inequilateral; color in KOH pale ochraceous tawny, in
Melzer's scarcely changing; wall about 0.25 /t thick.
Basidia 4-spored, 18-22 X 6-7 /z, clavate Ivaline in KOH, yellowish
in Melzer's reagent. Pleurocystidia scattered, 36-58(63) x 8-12(15) A,
fusoid-ventricose with the "neck" narrowly elliptic in optical section
varying to typically fusoid ventricose with a straiglt neck and obtuse
aplex; wall thin, smooth, hyaline to yellowish in KOH. Content "empty"
or witli a plug of yellowish colloidal material in the apex. Cheilocystidia
clavate to fusoid-ventricose or ventricose with the "neck" enlarged and
apex rotundled, smootlh, tlin-walled, content llyaline to yellowish. Caulocystidia in clusters 10-80 X 7-12 aL, cylindric to clavate, thin-walled,
walls smooth, yellowish in KOH; content "empty."
Gill trama with a central area of parallel hyaline thin-walled smooth
llhyphae 4-8 JLt in diam. which are non-gelatinous in KOH; sbl)llhmenilum
of loosely arranged non-gelatinous to subgelatinous (near gill edge)
llyplhae 2.5-3.5 pu in diam. Pileus cutis a gelatinous pellicle of narrow
lIyaline to yellowislh hlIypllae with numerous transverse creases as revived
(appearing crinkled); liypodermial region rtsty-fulvous in KOH, hyphae
floccose and fairly heavily incrusted. Context lhyphae interwoven, thinwalled, walls smooth (except near hlylodermium) and cells inflated. All
llyplhae inamylloid. (lamp connections present.
Romell's painting with the collection (no. 9782), shows a Pholiota
with olive in the coloration and a somewhat dingy stipe much as we
know the species in North America but the microscopic features are
different and as dried the basidiocarps are a very bright yellow. The
sublhynmeniuni is not truly gelatinous as revived in KOH. Sections compared give quite a different picture. The pleurocystidia are smaller and
have a strong tendency for a secondary enlargement beyond the main
ventricose portion in the area normally described as the neck. Also, the
spores are "small," as in some American collections.