LECCINUM MANZANITAE var. MANZANITAE Thiers, Mycologia 63:266. 1971

Illustrations: See Microfiche No. 34

Pileus (5)8-20 cm broad, globose to convex when young, broadly convex to pulvinate when mature; surface often shallowly to deeply pitted or reticulate, viscid to subviscid, especially with age, strongly appressed-fibrillose during all stages of development or occasionally tomentose, never glabrous, fibrils often more conspicuous toward the margin; color dark red ("bay" to "mahogany red" to "Mars brown" to "burnt umber") during all stages of development; margin incurved, with conspicuous sterile projecting cuticular segments. Context 2-4 cm thick, white when first exposed, slowly and erratically changing to fuscous with no reddish intermediate stage; color changes often more pronounced in young basidiocarps. Taste and odor mild.

Tubes 1-2.5 cm in length, adnate to shallowly or deeply depressed, pale olive ("pale olive-buff") when young, darkening to olive drab ("olive-buff" to "deep olive-buff") at maturity, staining dark brown ("buffy brown") when bruised; pores up to 1 mm broad, angular, concolorous.

Stipe 10-16 cm long, 1.5-3.5 cm thick at the apex, clavate to ventricose, solid; surface dry, conspicuously squamulose, squamules typically pallid when young, darkening to near fuscous with age, ground color white to whitish. Context white, slowly staining fuscous in apical portion when exposed, sometimes bluing in the base.

Spore print brown. Spores 13-17 X 4-5.5 Ám, ochraceous in KOH and Melzer's, fusoid to subellipsoid to subcylindric, inequilateral; walls smooth, moderately thick.

Basidia 27-32 X 6-9 Ám, clavate to pyriform, hyaline in KOH, four-spored. Hymenial cystidia 23-32 X 4-6 Ám, often obscure, scattered, hyaline in KOH, fusoid to clavate with narrow, elongated apices.

Tube trama obscurely divergent from a distinct central strand, hyaline in KOH, hyphae 6-8 Ám wide. Pileus trama hyaline in KOH, interwoven, homogeneous, hyphae 6-9 Ám wide. Pileus cuticle differentiated as a trichodermium of free, tangled hyphal tips, no evidence of gelatinization of hyphal walls, hyphae 8-12 Ám wide, some disarticulation of cells noted, walls smooth to sometimes obscurely roughened, contents ochraceous in KOH, reddish in Melzer's, pigment globules forming when mounted in Melzer's, terminal cells elongated and often noticeably tapered. Caulocystidia 35-45 X 9-14 Ám, clavate to mucronate to fusoid, staining dark brown in Melzer's and KOH, thin-walled, large cells occasionally interspersed, basidia sometimes present. Clamp connections absent.

Chemical reactions KOH-tubes pale red, then blackening; HNO3-tubes orange yellow; FeSO4-context pale gray.

Habit habitat, and distribution Solitary to scattered in soil under madrone and manzanita. This is by far the most common Leccinum in the coastal forests of California, where it has been observed associated only with ericaceous hosts. It has not yet been found in the foothilIs or mountain ranges. In the Santa Cruz Peninsula, where it is often abundant, it is frequently referred to as the "manzanita mushroom."

Material studied Marin County: Thiers 24654. Mendocino County: Thiers 8299, 9283, 10671, 18152, 21412, 21413, 23064, 24189, 24450, 24461, 24462, 24507, 24737. San Mateo County: Thiers 11200, 18059, 18336, 24735, 24736, 24755. Santa Cruz County: Thiers 12034, 14404.

Observations This is one of the large, massive boletes with caps that often weigh several pounds. It is distinguished by the very dark red color of the pileus, which is characteristically viscid even in dry weather, the conspicuously fibrillose surface of the cap, and the darkening of the context of the cap and stipe apex when exposed. These color changes are often somewhat erratic and may be very slow in developing; frequently, there are only localized areas in which the color change can be detected. Leccinum manzanitae is somewhat suggestive of L. ponderosum, but the context of the latter does not darken when exposed, it is not as deeply colored, and the pileus is glabrous. Leccinum constans, also associated with madrone in the coastal regions, is much paler in color, and the context remains unchanged in color when exposed to the air.

This fungus is one of the common edible mushrooms, and it is often gathered and dried as is done with Boletus edulis.

Online edition addendum

Other Descriptions and Photos: The Fungi of California

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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