Tylopilus bulbosus Halling & G.M.Muell.

Description

Basidiomata conspicua, pileo sicco tomentoso purpureo-brunneo marginem angularem, contexto mutabili, sapore miti, stipite pruinoso raro reticulato et tum imperfecto, poris hymenophori lilaceo-roseis coloratis ubi juvenibus.

Solitary to gregarious in soil of montane forests dominated by Quercus copeyensis C. H. Mueller, Q. oocarpa Liebm., and Q. seemannii Liebm. Widely distributed and often locally abundant in the northern to central Cordillera Talamanca of Costa Rica.

COSTA RICA. Cartago: Guarco, Estrella, ±5 km E of Interamerican Highway at km 31, near town of Estrella, 9°46'4''N, 83°57'19''W; 1717 m, 6 June 1997, Halling 7699 (NY, USJ). San José: Dota, San Gerardo, Albergue de Montaña, Savegre, ±5 km SW of Cerro de la Muerte, 9°33'2''N, 83°48'27''W; 2500 m, 8 August 1993, E. M. Pine 1050 (F, USJ); 11 August 1993, E. M. Pine 1064 (F, USJ); 6 November 1993, Halling 7136 (NY, USJ), Mueller 4609 (F, USJ); 7 November 1993, Halling 7141 (NY, USJ); 24 November 1993, Halling 7193 (NY, USJ); 20 June 1994, Halling 7312 (NY, USJ); 16 October 1994, Halling 7366 (NY, USJ); 19 October 1994, Halling 7393 (NY, USJ); 21 June 1995, Halling 7447 (NY, USJ); 11 June 1996, Halling 7668 (NY, USJ); 17 October 1999, Duguay 5 (NY, USJ); 3 July 2000, Halling 7983 (NY, USJ). Copey, 12 km S of Copey on road to Providencia, 9°35'19''N, 83°53'3''W, 2800 m, 20 October 1994, Halling 7399 (NY, USJ).

Tylopilus bulbosus is a large, conspicuous bolete that can be very common in some localities (e.g., the Savegre river drainage). The initial violet to purplish brown pigments give way to pale brown or brown tones with age, although when fresh, the violet colors are usually present on some portion of the basidiomata. The conspicuously lilac-rose colored pores are especially distinctive as is the mild taste (the latter uncommon in many tylopili). Based on Singer's (1986) circumscription of the genus, T. bulbosus would fit in section Oxydabiles by virtue of the mutable context, but differs from taxa admitted by him because of the violet to purple pigments. Even though T. bulbosus is phenetically similar to T. rubrobrunneus Mazzer & A. H. Sm. (eastern United States, Smith and Thiers, 1971) and T. williamsii Singer & Gómez (Costa Rica and southeastern United States, Singer et al., 1991), neither of which are mentioned in Singer (1986), T. bulbosus can be separated by the violet to purple colors, oxidation reaction of the flesh, mild taste, and pigmented pores.

Pileus 4.5--11(--13) cm broad, convex to plano-convex, dry, not hygrophanous, even or more often beveled at margin, tomentose to subtomentose to matted subtomentose, sometimes becoming finely areolate cracked when dry, purplish gray (13-14E5-4), dark violet brown (11F7-6-5), dark brownish purple (14-15F5-4), violet brown to dark ruby (11-12F-E4, 12F6-5-4), or dark red brown (9F5) with hints of violet (10F4), fading to dark brown (6-7F8, 7E4) to (6D-E7-6-5), eventually with decided violet to violet brown tones near margin, grayish reddish brown (9D4) to dull reddish grayish brown (8C-D3) and sometimes maculose-spotted with age. Flesh 1.5--3 cm thick, white, staining pinkish brown; odor mild or pungent but not idiosyncratic; taste mild. Hymenophore tubulose, adnexed or depressed; tubes up to 1.5 cm deep, nearest yellowish white (4A2) at first, with a decided pinkish flesh tint (6-7A-B3) with age, changing to avellaneous when exposed; pores a very pale pinkish purple to grayish rose to lilac rose (11B3), grayish red (11-12D5-4) when young, becoming white then pinkish flesh color with age, changing to brown when bruised. Stipe (6--)9--14(--17) cm x 10--15(--20) mm, 50 mm at base, extremely clavate to subbulbous, strict or curved, dry, pallid at apex (7D-E8-7) at first and concolorous with pileus (violet brown to purplish brown or dark red brown) below when young, browner with age and white to sordid yellow at base, frequently with olivaceous stains with age, pruinose to very minutely subscabrous-ridged (lens) to subpruinose or occasionally with a reticulum on upper 1(2) cm; reticulum sometimes not circumferential; interior solid, white above, staining pale brown to pinkish brown, white or yellow to yellowish olive below and staining pinkish brown; basal mycelium white. NH4: pale yellow on pileus.

Basidiospores in fresh deposit pinkish flesh colored, 10--14 x 4.2--4.9(--5.6) µm, mean Q = 2.53, smooth, subfusoid, inamyloid or rarely, lightly dextrinoid. Basidia 20--30 x 8--12 µm, clavate, hyaline, 4-sterigmate. Hymenophoral trama bilateral, with hyaline, inamyloid hyphae. Hymenial cystidia present as abundant pseudocystidia, 50--80 x 8--14 µm, smooth and thin-walled, narrowly to broadly fusiform to fusiform ventricose, hyaline or melleous in KOH, dextrinoid in Melzer's reagent. Pileus trama interwoven, smooth and thin-walled, hyaline, inamyloid. Pileipellis hyphae a simple, erect trichodermium when young, interwoven and suberect with age; elements 5-9 µm broad, hyaline or rarely with melleous, homogeneous content, smooth and thin-walled. Stipitipellis hyphae forming a hymeniform layer of caulocystidia and smaller cystidioles; caulocystidia 30--65 x 5--9 µm, smooth and thin-walled, narrowly fusiform to subcylindric, hyaline or with pale melleous contents. Clamp connections absent.

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Tylopilus bulbosus (image/jpeg)

Tylopilus bulbosus (image/jpeg)