The veiled species of Hebeloma in the western United States / Alexander H. Smith, Vera Stucky Evenson, and Duane H. Mitchel.

Introduction

15

In spore studies with Melzer's reagent in other genera, we have never
noted any tendency for the spore pigment to be soluble in the mounting medium. Many species of Hebeloma, especially those closely related to H. mesophaeum, have spores nearly colorless to yellowish in
Melzer's. However, in the present work, we reserve the term dextrinoid for a distinctive and reasonably prompt color change of the spores
to deep reddish brown. We have found this character useful in distinguishing one species from another. For example, those species with
large inequilateral spores tend to have distinctively dextrinoid spore
walls that are obviously ornamented. These features appear to be consistent and of value in defining taxa at the various levels below the
rank of subgenus. For the present, we consider the red "flush" in the
trama when treated with Melzer's, the dextrinoid debris, and the reddish brown spore reaction as independent characters.
The color of the spore deposit has been given prominence in
many taxonomic treatments of Hebeloma with a subgenus Porphyrospora reserved for those few species previously described as having
reddish to purple-brown spore deposits. In our work we have found
reddish brown spore deposits in both the veiled and nonveiled species,
and a gradation of spore color from light clay color to reddish cinnamon to purple-brown without a clear line of separation which could be
used taxonomically. Most species in the genus give a deposit which
when air-dried is dull cinnamon to clay color to "Verona Brown"
(distinctly reddish brown). In such large groups as the Strophariaceae
and the Coprinaceae this same spectrum of spore-deposit color is
found. In Hebeloma species in which the spores appear nearly hyaline
under the microscope, the deposit is usually clay color or paler.
Mounting such spores in KOH causes an accentuation of the yellowbrown tone, a color change which reminds one of the Strophariaceae,
in which the KOH fades the violet component of the spore color and
intensifies the yellow component.
Taste and Odor. Appreciation of taste and odor varies markedly
from one individual to another. Some people are genetically unable to
taste bitter, and the sense of smell is poorly developed and frequently
lost in many people. Only fresh material gives sufficient odor to be
recognizable as a rule and though some dried specimens have an odor,
it is frequently contaminated by insect repellents or other chemical
odors in the herbarium. Nevertheless, taste and odor have been used
to advantage, in combination with other characters, to distinguish certain species of Hebeloma. We have used six general categories:
1. Sweet to nauseatingly sweet, usually associated with a fragrant
odor, is unusual in the genus but readily recognized by most
people.