A monograph on the genus Galerina Earle / by Alexander H. Smith and Rolf Singer.

Smith * Singer

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The span of variation in these characters in the genus as a whole extends from a smooth non-wrinkled layer, or the absence of such a layer,
to one which breaks up leaving prominent warts and wrinkles (ridges) over
most of the spore. The degree of roughness is often correlated with other
characters. In some species the entire exosporium tends to loosen and fit
over the episporium as a sack, and is very wrinkled to warty. This condition appears to be rather frequent in tropical and subtropical species, but
is not limited to them. In other species the exosporium adheres tightly over
most of the surface which then appears smooth, but loosens in certain places
around the plage area so that in face view blister-like inflations are seen as
"ears") on either side of the plage. Or the loosening may extend completely
around the hilar end of the spore, making it evident that the outer layer fits
tightly over the spore except at the basal portion. Although KUhner
observed and illustrated this character in his G. calyptrospora, he missed its
significance, very likely because the European flora is very poor in species of
the group showing this character. As a result, he included (1935) some quite
distinc: Galerinae under the name G. hypnorum. The results of our study of the
North American Galerinae have clearly demonstrated that a large and
natural group has this type of spore.
In other species the spore appears almost smooth, but a faint ragged
line delimits the plage. Finally a completely smooth spore is encountered.
Species with such spores are clearly peripheral for the genus and assignment
to Galerina is made on other characters.
At the opposite extreme we find a rough spore without a smooth plage.
Such species usually lack clamp connections, and, as in smooth-spored
species, assignment to Galerina is based on other characters, particularly the
Mycena-like aspect. Some species with clamp connections show only rudimentary plage formation, and in some species one can find spores in which
the exosporium covers the plage area but is free except at the boundaries of
the area-thus forming a blister which, if it breaks, leaves the plage smooth
but marked by a ragged boundary line. Presumably this blister formation
is typical for all species with a well delimited plage.
One of the interesting discoveries made in the course of this investigation was that there are two species in the genus in which a bandlike thickening of the wall occurs a short distance back from the apex of the spore, so
that in optical section there appear to be two thickenings in this region, one
opposite the other. The presence of this band often gives the face view of the
spore a slight angularity. The significance of this character is not clear at
present.
The episporium may be thick and dark colored or thin and very pale,
and these differences appear to have definite taxonomic significance. They
are reflected in the color of the spore deposit as well as in the color of individual spores seen under the microscope. The pigment is in the wall and as
a rule becomes much darker in KOH.
A small apical pore is present in a few species and it is not difficult to
envisage a progression from this group (Section Porospora) to the Conocybe
type of spore (truncate apex), or, which is more important, a transition to