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

Smith ~ Hesler

17

an obscurely inequilateral spore in profile the ventral line in optical
section is humped slightly on the side toward the apex-if one were to
make a medial transverse section of the spore. The dorsal line, however,
is "humped" slightly back of this medial section or about at the medial
position, but in a transverse line across the spore the two humps do not
coincide at their peaks. The degree to which the suprahilar plage is depressed will then be the factor most important in determining the category: if slightly depressed the spore is said to be somewhat inequilateral.
If not or scarcely at all depressed the term obscurely inequilateral is
used. If the suprahilar depression is distinct and the spore is drawn out
to a more or less narrowed apex the unqualified term inequilateral
applies. The term bean-shaped or phaseoliform means exactly what it
says: the profile of a navy bean.
Spores in Pholiota vary with the species from small (3.5-5 x 2.5-3 u)
in P. flammans, to relatively large in P. albocrenulata (10-14-18 X 5.5 -7-8 /.). In the bulk of the species, however, the spores fall in a range in
length of 6-9 JL. In subgenus Flammuloides this is particularly true;
there is one group of about fifty species in which they measure 5-7.5 X
3.5-4.5 JL.
Although reactions of the spore wall with iodine (Melzer's solution)
have not been emphasized greatly in the study of brown spored agarics,
we have found a group of species (subgenus Flammula) in which the
spores are a darker reddish brown in it than when revived in KOH-in
other words they are somewhat dextrinoid. This feature correlates so well
with absence of pleurocystidia and bright yellow pilei that it is used as a
major feature in redefining the subgenus. In P. brunneidisca a few spores
show a violet-brown coagulated content in Melzer's reagent.
Basidia. These structures are normally clavate and 4-spored, and are
of such uniformity in Pholiota that their importance in taxonomy as
morphological structures showing differences is minor indeed. It is true
that in some species they are relatively large, up to 40 X 10 L/, but most
often they are 22-28 X 5-6 Ft or smaller. In some species both 2- and
4-spored basidia were found, but none were consistently 2-spored only.
At times the content of the cell may be brown in KOH, but this is not
a constant feature of the type that can be used in species recognition.
However, it is of theoretical interest in that in this genus some hyphae
and their end-cells can serve as a container for certain compounds and
still perform such basic functions as producing spores. More will be said
of this feature under the heading of gloeocystidia.
Pleurocystidia. Sterile end-cells interspersed among the basidia in the
hymenium are common and often conspicuous. In form, one encounters
two general types: 1) those which project conspicuously beyond the
hymenium, and 2) those which are more or less buried in it and project
only slightly or not at all.
1. The projecting type. The term Flammula-type is no longer appro