North American species of Lactarius / L. R. Hesler, Alexander H. Smith.

Introduction

5

least a somewhat cellular cuticle. We recognize Singer's subsection
as emended. His Aspideini is the same as our section Aspideini with
exclusion of L. uvidus and L. psammicola. Subsection Vietini, with
exclusion of stirps Necator is in part our section Tristes. We recognize Singer's stirps Necator as a section, the Atroviridi of subgenus
Piperites.
The classification of Singer (1975) closely follows the lines of his
1962 treatment. Sections 1 to 4 (Lactariopsidei, Venolactarius, Panuoidei, and Polysphaerophori) are not important in the area covered by
our work. Sections Dulces Heim and Albati (Bat.) Singer are important and are included in our subgenus Lactifluus for the most part.
Section Plinthogali, with the inclusion of L. xanthydrorheus Singer,
corresponds closely to our subgenus Plinthogalus. Section Russulares
sensu Singer corresponds rather closely to our subgenus Russularia.
However, his section Lactarius and our subgenus Piperites differ in
that his section includes some species we place in subgenus Tristes
and some, in Russularia. His section Dapetes is identical in scope with
our subgenus Lactarius.
Singer (1975) states that he lists 86 species as admitted to the
genus. We recognize over 250 for North America. With a much larger
sample from a more restricted area, it is logical to expect that many
of the distinctions Singer has made between sections will be found
inadequate, especially as they involve such routine features as color
of spore deposit, taste of context, pattern of spore ornamentation, and
so forth. In fact, our study has shown that all the major taxa in the
genus overlap when they are based on more than a single character.
This is true regardless of whose classification is considered.
Other Infrageneric Classifications of Lactarius
These classifications are numerous, and in most works no indication of the rank of a group is given; nor is a type species often indicated for any group regardless of level. In the following, we have
designated type species for a number of the divisions of the genus as
proposed by Fries. This is basic to a disposition of the taxa proposed
by later workers. Kauffman (1918), for instance, stated that the Piperites
and Russularia ranked as subgenera in his work. He treated nine
sections identified only by Roman numerals. Burlingham (1908) recognized as sections Piperites, Sublimacina, Limacina, Russularia, and
Dapetes for the genus. In her next work (1910b) she recognized 18
groups of lower rank, all at the same level, which, in our estimation,
should be recognized as subsections. Konrad and Maublanc (1952)
in their work clearly indicate the recognized sections, but used the
term "groupe" for the next lower level of taxa. We have not tried to