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Page number:133 
Remarks (internal):Entoloma olivaceocoloratum is recognized in the field by its large, tricholomatoid basidioma, its olive to olive-brown, dry, opaque pileus with irregularly crenulate margin, its yellowish stipe that stains brown with handling and its lack of a distinctive flavor or odor. Microscopically E. olivaceocoloratum is distinctive in its combination of isodiametric basidiospores usually <8.0 µm diam, its cylindroclavate basidia with wide sterigmata, its lack of hymenial cystidia and the presence of refractive hyphae just below the pileus surface. Because of the tricholomatoid stature, the brown, dry, opaque pileus, and longitudinally striate stipe, E. olivaceocoloratum is classified in Entoloma section Lividoalbum Largent.
Kobayashi et al (2005) demonstrated EM formation by Entoloma sepium (Noull. & Dass.) Richon & Rose of section Lividoalbum. All species of section Lividoalbum appear to fruit in association with EM woody vascular plants and are putatively EM (Largent 1994). Entoloma olivaceocoloratum is presumed to be an EM associate of D. corymbosa.
The mild flavor and odor E. olivaceocoloratum is similar to that of E. lividoalbum (Kühn. & Romagn.) Kubicka forma inodoratum Largent. However the latter taxon can be differentiated from E. olivaceocoloratum by its dark yellow-brown pileus, its white stipe that does not discolor and its larger basidiospores, 7.7-11.7 x 6.1-9.6 µm (Largent 1994).
Entoloma olivaceobrunneum Hesler from North Carolina and Tennessee has a similar stature, pileus color, pileal margin and basidiospore morphology as E. olivaceocoloratum. However E. olivaceobrunneum is distinct because of its slightly viscid, hygrophanous pileus, its farinaceous odor and flavor, the white stipe that does not discolor, the presence of cheilocystidia and gelatinous hyphae in the pileipellis (Hesler 1967).
In Guyana Entoloma rugosostriatum sp. nov. is the only other species of Entoloma that currently can be confused with E. olivaceocoloratum because of its similar stature and pileus color. Entoloma rugosostriatum can be differentiated from E. olivaceocoloratum by its smaller, obscurely angular isodiametric basidiospores (on average 6.9 x 6.8 µm vs. 7.8 x 7.2 µm for E. olivaceocoloratum), clavate cheilocystidia, rugose pileus near the disk, translucent-striate pileal margin that extends beyond the lamellae, and nonstaining stipe.
Other species that could be confused with E. olivaceocoloratum are E. andinum Dennis from Venezuela, E. congregatum Stevenson from New Zealand and E. viridans (Fr.) P. Karst. from Sweden and Wales, all of which possess brownish pilei and relatively large basidiomata. Entoloma andinum can be distinguished by its umbrinus pileus and stipe that respectively lack olive or yellow tones and its gray lamellae (Dennis 1970). Entoloma congregatum has heterodiametric spores, adnate lamellae and a creamy to light fawn, silky striate, hollow stipe that is much smaller, 50-70 x 5-10 mm (Horak 1973). Entoloma viridans can be differentiated by its smaller pileus (30-40 mm diam) and stipe (40-60 x 6-9 mm), each with distinctly greenish tinges (Noordeloos 1992).
 
Description type:Original description 
Description:Entoloma olivaceocoloratum Largent et T.W. Henkel, sp. nov. Fig. 1
Basidioma fleshy. Pileus 93-143 mm broad, 15-29 mm tall, broadly convex with a broad umbo, olive to olive-brown (3C7-3D7-4C7-4D7), darker over disk (4F6-7); pileal surface a matted tomentum under lens, otherwise appearing glabrous, opaque, dry; margin irregularly crenate and slightly in-rolled, eroding with age. Lamellae mostly sinuate, subdistant, thick, white then dull pink (4A3-5A3 KW), 3-11 mm broad at margin, 6-21 mm centrally, 2-4 mm at stipe; margin entire to finely serrulate. Stipe 85-134 x 17-22 mm, equal, slightly attenuated at extreme base, yellow (2A3-3A3), staining brown progressively with handling (5B5-4B5 KW), coarsely longitudinally striate throughout, striations broadly anastomosing toward apex; basal mycelium white, over lower 15-41 mm of stipe. Pileus trama white, unchanging, subsolid, 0.5 mm thick at margin, 3-4 mm over lamellae, 16-22 mm over stipe apex. Stipe trama white, unchanging, solid. Odor pleasantly fungal; flavor mild.
Basidiospores 5-6 sided in all views, isodiametric to subisodiametric in side view, isodiametric in apical view, angles distinct, 6.9-9.4 x 6.2-8 µm, ( = 7.8 ± 0.7 µm x 7.2 ± 0.6 µm, E = 0.94-1.23, Q = 1.1 ± 0.07, L-D = -0.47-1.74 µm, AL-D = 0.61 ± 0.52 µm, n = 23). Basidia 2-4 sterigmate, sterigmata up to 2 x 1 µm; mostly cylindroclavate, occasionally narrowly clavate, 34.9-44.6 x 5.6-8.8 µm, ( = 39.6 ± 2.0 x 6.9. ± 1.1 µm, E = 4.3-7.2, Q = 5.9 ± 1.1, n = 9). Hymenial cystidia absent. Lamellar trama hyphae subparallel, broad, 40.9-110.6 x 7.1-12.1 µm; sub-hymenium indistinct. Pileipellis a cutis with debris attached to surface; pigment dark when sections viewed in 3% KOH, persisting up to 20-30 min, probably cytoplasmic, not encrusting; suprapellis composed of cylindric hyphae, 2.2-2.7 µm wide with the end cells 41.9-49.9 µm long and the remainder composed of slightly broader hyphae with longer cells, these 50.1-77.8 x 5.8-6.5 µm. Pileus trama hyphae short and broad with frequent intervening air spaces, appearing puzzle-shaped, more broad than hyphae of the pileipellis, 28.5-88.2 x 8.6-22.6 µm. Stipitipellis a hyaline cutis composed of cylindric hyphae. Stipe trama hyphae parallel to subparallel. Refractive hyphae absent in the trama of the stipe, present in the subpellis of the pileus, rare to scattered in the lamellar trama. Clamp connections present on the hyphae of the lamellar trama, pileipellis, and stipitipellis; indistinct at the bases of the basidia and pileipellis end cells.
Habit, habitat and distribution. - Solitary to scattered on root mat in monodominant D. corymbosa forest; known only from the type locality.
Etymology. - Olivaceus, coloratis, Latin; referring to the olive color of the pileus.
Specimens examined. - Guyana. Region 8 Potaro-Siparuni: Pakaraima Mountains, Upper Potaro River, 5°18'04.8''N, 59°54'40.4''W, elevation 710 m, vicinity of Potaro base camp, under D. corymbosa, 20 Jun 2006, Henkel 8855 (Holotype: BRG; Isotype: HSU; MycoBank No. MB 510895)
 
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