SUILLUS IMITATUS Smith and Thiers, Contr. Toward a Monogr. of N. Am. Sp. of Suillus, p. 40. 1964
Pileus 4-12 cm broad, obtuse to convex, expanding to nearly plane or the disc depressed, surface glutinous and glabrous; color brown to reddish brown ("orange cinnamon" to "cinnamon"). Context up to 2 cm thick, soft, pale yellow, slowly becoming dingy with a faint tawny cast where exposed (no definite color change). Taste mild; odor acidulous.
Tubes 7-15 mm deep, adnate or slightly depressed at the stipe, with decurrent lines up to 5 mm down the stipe apex, readily separable from pileus, yellow ("deep colonial buff") and becoming a little darker than honey yellow when older; pores 2-3 mm long, 1.5-2 mm wide, staining dull reddish brown, angular or irregular and elongated radially, the arrangement not obviously boletinoid.
Stipe 3.5-6 cm long, 1.5-2.5 cm thick, tapering abruptly at base, solid; surface at apex with decurrent tube lines, or faintly reticulate and smooth from there to the annulus, matted fibrillose and more or less ridged below the annulus, not glandular dotted anywhere; color yellow ("colonial buff") with tawny mottling above, pallid mottled cinnamon to pinkish cinnamon below, some finally discolored grayish brown to umbrinous; annulus band-like, well developed to faint, consisting of felty-tomentose soft material with some gluten adhering along the edges, colored white to dingy pallid and discoloring brownish. Context rather bright yellow, quickly becoming blue in basal half or third, elsewhere fading and becoming discolored like the pileus context.
Spore print color unknown. Spores 7-9 X 4-4.5 Ám, narrowly elliptic in face view, subelliptic in profile, pale ochraceous in KOH, smooth, walls slightly thickened.
Basidia 18-23 X 5-6 Ám, four-spored, hyaline to yellowish in KOH, clavate. Hymenial cystidia 36-54 X 7-10 Ám, solitary or in bundles, subcylindric, narrowly clavate or submucronate, thin-walled, hyaline or with ochraceous to yellow-brown content, typically with amorphous bister (in KOH) pigment around the base of the bundle and at times over individual cystidia.
Tube trama of divergent hyphae, no laticifers seen. Pileus trama of interwoven hyphae and poorly differentiated laticiferous hyphae with considerable amorphous pigment particles scattered through the trama when revived in KOH. Pileus cuticle an ixotrichodermium composed of repent narrow hyphae. Caulocystidia clavate to subcylindric, in fascicles, content ochraceous to tawny but lacking incrustations around the base or anywhere else. Clamp Connections absent.
Chemical reactions unknown.
Habit, habitat, and distribution This species has not yet been recorded from California, but is known from both Oregon and Washington. In those states it occurs in spruce-fir forests and, since both of these hosts occur in the northern portion of California, it has been included with the expectation that it will eventually be discovered within the state.
Observations The description of this species is adapted from an earlier publication of Smith and Thiers. This fungus appears closely related to two rather common species in California. It has been confused, for example, with Suillus lakei, but S. imitatus has a glabrous pileus. In addition S. lakei, so far as is known, is associated only with Douglas fir. Suillus caerulescens, apparently the closest relative of S. imitatus, is distinguished by its longer spores, the presence of scattered, fibrillose scales on the pileus, and paler colors. Suillus caerulescens is also associated only with Douglas fir, at least in 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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