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

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THE BOLETES OF MICHIGAN

honey-yellow to a more greenish yellow; pores angular, honey-yellow,
1-2 mm broad, slowly staining ochraceous where bruised.
Stipe 3-6 cm long, 8-13 mm thick, equal, solid, pale yellow
within, surface under a lens of appressed, matted fibrils to fibrillosesquamulose with yellow-brown fibrils ("bister" to "tawny-olive"), instantly cinnabar-orange in KOH, at base matted-fibrillose and pallid
yellowish from the fibrils.
Spore deposit dark olive. Spores 12-18.5 X 3.5-5 j, smooth, in
face view boat-shaped, in profile narrowly inequilateral, color bright
yellow revived in KOH, dingy yellowish tan with a gray shadow in
Melzer's, walls slightly thickened.
Basidia 4-spored, 3540 X 8-10 u, clavate, yellow in KOH, hymenium bluish black crushed out in Melzer's but no amyloid elements
showing under the microscope. Pleurocystidia abundant, hyaline to
yellow in KOH, 35-50 (60) X 8-14 u, fusoid-ventricose, tapered to an
acute apex, rarely obtuse. Cheilocystidia similar to pleurocystidia but
shorter and with shorter necks and more obtuse apices.
Trichodermium of pileus of hyphae with hyaline incrustations on
many which disappear in Melzer's and more slowly in KOH, the hyphae
4-9 i wide, scattered in the layer are cells inflated to 15-20iu and
yellowish to hyaline under the microscope (in KOH), terminal cells
tubular with apex obtuse. Context bluish black in Melzer's but no
amyloid hyphae present, in KOH the pileus tissue canary-yellow at first,
soon fading. Clamp connections absent.
Habit, habitat, and distribution.-Solitary to cespitose on basidiocarps of Scleroderma vulgare, rare in Michigan but known from
Tahquamenon Falls State Park, Pellston, and Otis Lake in Barry County.
It is more common in the southeastern states.
Observations.-This is a readily recognized species by virtue of its
parasitic habit of growing on basidiocarps of Scleroderma, the dark
fibrils on the stipe, and the brilliant colors when tested with KOH.
Subsection VERSICOLORES, subsect. nov.
Tubuli tactu lutei vel brunnei sed non caerulei.
In this group there is no change to blue on the injured surface of
the hymenophore. The pilei are variously colored depending on the
species, and many species have short, inflated cells in the trichodermial
hyphae of the pileus.
Type species: Boletus illudens.