The boletes of Michigan, by Alexander H. Smith and Harry D. Thiers.

INTRODUCTION

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we are still at the "Alpha" level (beginning stage) in our understanding
of species per se, and we really have little knowledge of their distributions based on an adequate sample for the areas considered. Past estimates are hopelessly inadequate. It is hoped that the present work will
stimulate the detailed study of boletes in other states so that the degree
of diversity in the group as a whole can be made evident and the
peculiarities of distribution properly documented. For instance, why
should Tylopilus eximius be frequent in New England and rare in
Michigan? Most New England species are common here.
No work which brings together for the first time what is known of
a large group of fungi for an area as diverse as the state of Michigan can
hope to be "complete," as has been pointed out. The problems that
remain involve field work in the western part of the Upper Peninsula
and in the southwestern corner of the Lower Peninsula. More time
should also be spent on the limestone areas of the state. However,
because boletes fruit at the whim of the weather, one must follow the
rain pattern each season, emphasizing different geological formations
secondarily. There are still many complex groups in need of further
study. For example, it is only in the past five years that we have finally
realized the diversity which exists in Leccinum, and we are now busy
collecting in old as well as new areas to obtain a representative sample
of the genus.
GENERIC SEGREGATES FROM BOLETUS
AND THEIR RELATIONSHIPS
When one raises to family rank the group of species comprising
Boletus (sensu Fries) and includes in addition Strobilomyces and
Boletinus, certain problems immediately confront the investigator. As is
evident from the number of genera described in efforts to arrive at a
natural classification of the boletes, there have always been-and for that
matter still are-strongly diverging opinions as to how generic lines
should be drawn for the group. This is not the place, in an account of a
state flora, to review the long history of generic segregates from Boletus,
for it started in 1821 with S. F. Gray, and January 1, 1821, is the
starting date for the nomenclature of the group. Some justification,
however, for the classification we are proposing seems appropriate.
Of the genera we recognize, there seems to be no significant difference of opinion among current investigators on Strobilomyces, Gyroporus, Phylloporus, or Pulveroboletus (in the sense of the type species).