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

4

THE BOLETES OF MICHIGAN

financed; in part by the senior author personally, in part by the University of Michigan Herbarium field expedition funds, in part by grants
from the Faculty Research Fund of the University of Michigan, and in
part as incidental effort while collecting in other groups, such as Pluteus
and Rhizopogon, on grants from the National Science Foundation.
A complete set of the specimens reported here has been deposited
in the University of Michigan Herbarium. All color terms within quotation marks indicate that the plate of that name in R. Ridgway, Color
Standards and Color Nomenclature, matched the fungus part designated.
Ridgway terms not set off by quotation marks indicate an approximation of the Ridgway plate of that name. The term Melzer's is used as an
abbreviation of Melzer's reagent, the well-known chloralhydrate-iodine
solution now used universally in the study of the fleshy fungi.
FORMULAE USED IN BOLETE STUDIES
1. Potassium hydroxide (KOH): A 2.5 percent aqueous solution.
2. Ammonia: (NH40H): A 14 percent (approximately) aqueous
solution.
3. Iron salts (FeSO4 or Fe2C2): A 10 percent aqueous solution.
4. Melzer's reagent:
KI........ 1.5 gr. Water............. 22.0 gr.
Iodine..... 0.5 gr. Chloral hydrate..... 22.0 gr.
The drawings for figs. 20 through 123 were made with the aid of
a camera lucida. The magnification for the spores as reproduced is about
1650 X; for the hyphae and hyphal cells and cystidia it is about
650 X. The drawings were made from type specimens unless otherwise
indicated, except for European species which have been illustrated from
Michigan collections.
THE SPORES
The features of the spores used in identification are the color in
mass as obtained from air-dried spore deposits, size, absence or presence
of ornamentation and if ornamentation is present the type and pattern
shown, thickness of the wall and whether there is a germ pore at the
apex, and the color as observed under the microscope in mounts in
Melzer's and in weak potassium hydroxide (KOH).