TYLOPILUS FERRUGINEUS (Frost) Singer. Am. Midland Nat. 37: 106. 1947
Pileus 5-7 cm broad, obtusely convex to convex when young, typically becoming broadly convex to plane or shallowly depressed to highly irregular or undulating with age; surface dry, smooth, not rimose or areolate, tomentose to velutinous when young, often becoming glabrous with age; color dark brown ("Verona brown" to "snuff brown" to "warm sepia" to "bister") during all stages of development; margin incurved, becoming decurved, entire when young, often becoming somewhat lacerate with age. Context 1.5-2 cm thick, white to pallid ("pale pinkish buff" to "pale olive-buff"), unchanging with age or when exposed. Taste and odor mild.
Tubes 0.5-1 cm long, deeply depressed, flesh color (pale cinnamon-pink" to "pale pinkish cinnamon" to "light pinkish cinnamon"), often with age assuming a yellowish cast, changing to brown when bruised; pores small, less than 1 mm broad, angular, concolorous, readily changing to brown when bruised.
Stipe 3.5-7 cm long, 1-2 cm thick at the apex, somewhat ventricose to equal or tapering sharply at the base, solid; surface dry, pruinose to obscurely farinose to occasionally fibrillose, in some, obscure reticulations on the apex; color white to pallid ("pale pinkish buff"), readily staining brown when bruised. Context white, staining brown when bruised or exposed.
Spore print color not determined. Spores 8-11 X 3-4 Ám, hyaline in KOH, pale ochraceous in Melzer's, occasional spore dextrinoid, subcylindric to subfusoid, inequilateral, walls smooth, thin.
Basidia 24-28 X 5-8 Ám, clavate, four-spored, hyaline in KOH and Melzer's. Hymenial cystidia 26-37 X 6-9 Ám, clavate to cylindric to subfusoid, hyaline in KOH, dark ochraceous and appearing incrusted when mounted in Melzer's, thin-walled.
Tube trama obscurely divergent from a relatively broad central strand, hyaline in KOH, strand somewhat pale yellow in KOH, hyphae 3-5 Ám wide. Pileus trama interwoven, homogeneous, hyaline in KOH. Pileus cuticle differentiated as a compactly interwoven trichodermium, hyaline to pale ochraceous in KOH, dark brown in Melzer's, hyphae 3-5 Ám wide. Clamp connections absent.
Chemical reactions not determined.
Habit, habitat, and distribution Cespitose to gregarious in soil in mixed woods. Known only from a single collection made in the vicinity of Grass Valley and Nevada City.
Material studied Nevada County: Thiers 9683.
Observations The identification of this collection is somewhat tentative and was made with the use of Snell and Dick's manual on northeastern boletes. It seems to match their description and illustration. It is distinguished most readily by the very dark brown color of the pileus and stipe, the very firm consistency of the context, and the relatively small spores.
The Boletes of California
Copyright © 1975 by Dr. Harry D. Thiers
Additional content for the online edition © 1998 by Michael Wood, Fred Stevens, & Michael Boom
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