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

BOLETUS 287
8-10 p near the apex and then tapered, in Melzer's the content orangeochraceous. Hyphae of context 4-15 p wide, interwoven, content yellowish to hyaline in Melzer's, no amyloid material seen. Clamp connections
absent.
Habit, habitat, and distribution.-Scattered under oak on thin soil,
Waterloo Recreation Area, Waterloo, September 5, 1965, Florence
Hoseney.
Observations.-The diagnostic features are the viscid pileus with
the cuticular hyphae showing a slime-coating under the microscope, the
basically shallow adnate (to stipe) tube layer, and the 'fact that the pilei
dry with tints of rose readily visible. Nothing is known as yet about the
edibility of this variety, which is reason enough for not recommending
it. The stirps is to be regarded as dangerous.
Section TRUNCATI Smith & Thiers, sect. nov.
Sporae truncatae vel subtruncatae.
Typus: Boletus truncatus.
In veiw of the importance attributed to spore ornamentation in
the boletes by previous investigators, and to the presence of an apical
pore in spores with somewhat thickened walls throughout the fleshy
fungi generally, we believe this group should be given more recognition
than it has received in the past.
KEY TO SPECIES
1. Spores 9-12 x 4-5 A................................... 2
1. Spores 11-15 M long or 5-7 M wide.............. (see B. betula also) 3
2. Stipe rhubarb-red from pruina............ see Bole'tellus intermedius
2. Stipe pruina yellowish brown................. B. subdepauperatus
3. Taste bitter to disagreeable, pileus seldom areolate........... B. patriciae
3. Taste mild, pileus typically areolate at maturity.................. 4
4. Spores 4.5-6.5 (7) u wide, pileus soon with conspicuous red tones...................................... B. truncatus
4. Spores 4-5 u wide; pileus lacking pronounced red tones....................................B. porosporus var. americanus