BOLETUS ABIETICOLA sp. nov.

Pileus 9-13 cm latus, siccus, appresso-fibrillosus demum fibrilloso-squamosus, subroseus, maculis alutaceis vel flavis. Contextus albus vel subflavus, immutabilis vel raro caerulescens. Sapor et odor mitis. Tubuli 1-2 cm longi, flavi tactu caerulei; pori 1 mm lati, concolores, tactu caerulei. Stipes 9-13 cm longus, 4-5 cm crassus, clavatus vel subbulbosus, siccus, reticulatus, apice flavus, basi rubicosus. Sporae 14-17.5 X 4.5-5.5 Ám, ellipsoideae vel subfusoideae vel subcylindricae. Cystidia 40-50 X 4-7 Ám, cylindrica vel lageniformia vel subclavata vel subfusoidea. Cuticula intertexta. Holotypus (no. 38653) a Win. Bridge Cooke lectus prope Mt. Shasta, Siskiyou County, August 8, 1967; in Herbarium San Francisco State University conservatus.

Pileus 9-13 cm broad when mature, convex when young, becoming pIano-convex to plane at maturity; surface dry, appressed fibrillose, forming more or less imbricated fibrillose scales that remain readily apparent even when dried, occasionally almost white; color light rose with tan-colored spots interspersed and appearing yellow under the scales; margin incurved, entire. Context up to 2 cm thick, white to pale yellow, usually unchanging, occasionally slowly changing to blue in irregular areas when exposed. Taste mild, sweet; odor mild.

Tubes 1-2 cm in length, adnate to adnexed, shallowly depressed with age; yellow ("lemon yellow") when young, darkening and with greenish tints when mature, changing to blue when bruised or exposed; pores up to 1 mm broad, angular, concolorous, changing to blue when bruised.

Stipe 9-12 cm long, 4-5 cm thick at the apex, 5-6 cm thick at widest point, clavate to subbulbous, solid; surface dry, strongly reticulate over all except basal portion; color yellow, reddish at base, reticulum yellow; context white except reddish at the base, unchanging when exposed.

Spore print color unknown. Spores 14-17.5 X 4.5-5.5 Ám, pale ochraceous in KOH, ochraceous in Melzer's, ellipsoid to subfusoid to subcylindric in face view, inequilateral and ventricose in profile, walls thin, smooth.

Basidia 22-27 X 8-10 Ám, one-, two-, and four-spored, guttulate in KOH, clavate, hyaline; hymenium bright rust-red color in Melzer's, hyaline with scattered yellow areas in KOH. Hymenial cystidia 40-50 X 4-7 Ám, scattered to rare, inconspicuous, cylindric to pyriform to subclavate to subfusoid, hyaline in KOH and Melzer's, thin-walled.

Tube trama strongly divergent, hyaline and gelatinous in KOH, hyphae 7-8 Ám wide. Pileus trama interwoven, homogeneous, hyaline in KOH. Pileus cuticle a tangled trichodermium of hyphae with occasional erect hyphal tips, hyaline spiral incrustations on most hyphae, contents staining bright red to tawny in Melzer's, hyphae 8-10 Ám wide. Stipe cuticle composed largely of fertile basidia. Clamp connections absent.

Chemical reactions unknown.

Habit, habitat, and distribution Known only from the coniferous forests of higher elevations.

Material studied Siskiyou County: Cooke 38609, 38610, 38611, 38653 type.

Observations This species obviously belongs to the Boletus appendiculatus-B. fechtneri complex and has been alternately called one or the other of these for several years. The association with firs (Abies) has not been noted for either of the above species. The colors of the pileus, and especially the imbricated, fibrillose scales on the surface of B. abieticola, are distinctive; the spores are slightly larger than either B. appendiculatus or B. fechtneri, and the cystidia are differently shaped. The general arrangement of the spirally incrusted hyphae of the cuticle is also distinctive.

Edibility unknown.

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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