LECCINUM AURANTIACUM (Bulliard ex Saint-Amans) S. F. Gray, Nat. Arr. Brit. Pls. 1:646. 1821
Boletus aurantiacus Persoon, Mycol. Europ. 2:147. 1825.
Ceriomyces viscidus Murrill, North Am. Flora, 9:139. 1910.
Leccinum versipelle Snell apud Slipp and Snell, Lloydia 7:58. 1944.
Illustrations: See Microfiche No. 28
Lange, J. E., and M. Lange, 600 Pilze in Farben, p. 189.
Leclair, A., and H. Essette, Les Bolets, pl. 60.
Romagnesi, H., Nouvel Atlas des Champignons, pl. 136.
Singer, R., Die Rohrlinge, Teil 11, pl. XXIV, figs. 1-5.
Smith, A. H., Mushrooms in Their Natural Habitats, Reel V.
Smith, A. H., and H. D. Thiers, The Boletes of Michigan, pl. 70.
Snell, W. H., and E. A. Dick, The Boleti of Northeastern North America, pls. 68, 69.

Pileus 8-15 cm broad, convex to obtuse to pulvinate when young, becoming convex, broadly convex to plano-convex with age; surface dry, dull, uneven, or roughened, finely to matted-fibrillose when young, unchanging or appearing glabrous when older, sometimes finely and obscurely areolate; color bright rust brown to brick red ("ferruginous" to "rufous" to "apricot-orange") during all stages of development; margin incurved, with a conspicuous sterile band. Context 2-3 cm thick, white when first exposed, changing to vinaceous to near flesh color ("testaceous"), then to gray to bluish gray ("fuscous") or black. Taste and odor mild.

Tubes 1-2 cm long, adnate to depressed when young, becoming deeply and narrowly depressed with age; when young pale olive ("pale olive-buff" to "deep olive-buff" to "olive-buff"), darkening to olive drab ("dark olive-buff") or becoming brown ("Wood brown") at maturity; pores 0.5-1 mm broad, angular, staining olive to olive brown to vinaceous brown when bruised.

Stipe 10-17 cm long, 2-3 cm thick at apex, clavate to ventricose, becoming equal, often narrowed at the base and apex, solid; surface dry, ground color whitish to white, occasionally staining blue in base, squamules pallid at first, black or dark brown with age. Context white, staining as in pileus.

Spore print brown. Spores 12-13.5 X 3.5-4.5 Ám (spores from single-spored basidia up to 28 Ám long), fusoid to subellipsoid, pale ochraceous in KOH, yellow brown in Melzer's, walls smooth, thin.

Basidia 30-55 X 9-11 Ám, clavate, hyaline in KOH, one- to four-spored. Hymenial cystidia 30-40 X 9-11 Ám, clavate to fusoid, scattered, deeply embedded, thin-walled, hyaline in KOH.

Tube trama hyaline in KOH, divergent, hyphae 5-8 Ám wide. Pileus trama interwoven, hyaline in KOH, homogeneous, hyphae 4-7 Ám wide. Pileus cuticle differentiated as a tangled trichodermium, pale ochraceous in KOH, hyphae 7-11 Ám wide, considerable disarticulation of cells noted, walls often asperulate, pigment globules formed when mounted in Melzer's reagent, terminal cells not strongly differentiated, no short intermediate cells present. Caulocystidia 38-48 X 8-13 Ám, dark brown in KOH, clavate, with large fusoid-ventricose cells interspersed. Clamp connections absent.

Chemical reactions FeSO4-context blue gray.

Habit, habitat, and distribution Scattered to gregarious in soil under pines in a forest composed largely of pines and aspens.

Material studied Madera County: Thiers 23608, 23611.

Observations It has been common practice to identify every rust-red colored Leccinum as this species; however, a critical reevaluation of this group has shown it to be composed of numerous species that can be easily distinguished. Leccinum aurantiacum sensu strictu is characterized by the brick-red colored pileus, flesh that turns reddish before becoming bluish black, and the development of pigment globules in cells of the cuticular hyphae when they are mounted in Melzer's reagent. As can be seen from the list of material studied, this is actually a rather rare species in California and has only been found in the vicinity of the Devil's Post Pile National Monument.

Edible and generally considered good. The dark discoloration of the flesh when dried or cooked is objectionable to some.

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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