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Page number:135 
Remarks (internal):Entoloma rugosostriatum is unique among Guyanese entolomatoid fungi due to its combination of a gray-brown, rugose, glabrous, moist pileus, translucent-striate pileal margin that extends beyond the lamellae, light yellowish to grayish-yellow lamellae, thick, clavate stipe that is acuminate at the extreme base and concolorous with the pileus, clavate cheilocystidia, 5-6 sided, small, weakly angular, isodiametric basidiospores, and lack of flavor and odor.
Based on the small size and weakly angled nodulose morphology of the basidiospores, E. rugosostriatum can be classified in Entoloma section Turfosa. Within section Turfosa, E. rugosostriatum is phenetically similar to E. turbidum (Fr. : Fr.) Quél. var. turbidum from the Netherlands, E. pseudoturbidum (Romangn.) Mos. from Europe, Rhodophyllus turbidiformis Romagn.-Gilles from Gabon and E. neoturbidum Pegler from the Lesser Antilles. Entoloma turbidum v. turbidum can be differentiated from E. rugosostriatum by its much paler pileus, its pale gray-brown, equal to only slightly enlarged stipe that measures 25-110 x 3-12 mm, its grayish lamellae that do not discolor and its lack of hymenial cystidia (Noordeloos 1992). Entoloma pseudoturbidum can be distinguished by its slightly lighter, hygrophanous pileus that is subviscid when moist, its pale brown lamellae, its silvery striate stipe that is (5-) 8-13 mm broad at the base, its rancid-farinaceous flavor and odor and its lack of cheilocystidia (Noordeloos 1992). Rhodophyllus turbidiformis can be separated by its fragile basidioma, equal stipe that measures 110 x 12 mm, pale brownish lamellae and lack of cheilocystidia (Romagnesi and Gilles 1979). Entoloma neoturbidum has a weakly hygrophanous, opaque pileus, distant lamellae that do not discolor, unpleasant odor, bitter flavor and longer and slightly broader spores, 7-9 x 6.5-8.5 µm (Pegler 1983).
Because of their basidioma statures, pileus colors and basidiospore sizes, E. cerinum Horak from New Zealand and E. corneri Horak from Singapore and Papau New Guinea could be confused with E. rugosostriatum. Entoloma cerinum can be differentiated by its lack of clamp connections, its deep yellow lamellae and stipe and distinctly angular basidiospores (Horak 1973, 1980). Entoloma corneri can be separated by its white lamellae, its distinctively angular basidiospores and its lack of clamp connections (Horak 1980).
Description type:Original description 
Description:Entoloma rugosostriatum Largent et T.W. Henkel, sp. nov. Fig. 2
Basidioma fleshy. Pileus 30-50 mm broad, planoconvex, moist, glabrous and shiny, linearly rugose near center, dark grayish brown (~6-7F2-3); margin decurved to nearly plane, extending beyond the lamellae up to 2 mm, translucent-striate, undulate; trama thin at the margin. Lamellae adnexed to emarginate, thick, subdistant, moderately broad (<6 mm midway between margin and stipe apex), light yellow to grayish yellow (~4A-B4-5) with handling. Stipe 50-70 mm long, 15-18 mm broad at apex, enlarging to 23 mm at base, narrowing at extreme base, longitudinally fibrillose with the fibrils ± concolorous with or slightly lighter than the pileus, faint yellowish over the apical 5-13 mm, solid with a hollow core. Odor and flavor none.
Spore deposit pinkish brown. Basidiospores 5-6 sided, rounded-angular, angles weak and thus appearing nearly nodulose, consistently isodiametric, 6.1-7.4 x 6.1-7.3 µm (av.= 6.9 ± 0.3 x 6.8 ± 0.3 µm, E = 0.9-1.1, Q = 1.01 ± 0.05, L-D = -0.9-0.75 µm, AL-D = 0.08 ± 0.35 µm, n = 21). Basidia 2-4 sterigmate, long-clavate and slightly tapered to the base, 36.6-45.5 x 6.1-8.9 µm (av.= 41 ± 2.9 x 7.1 ± 0.8 µm, Q = 5.8 ± 0.7, n = 12). Cheilocystidia abundant, forming a sterile layer on the lamella edge, short-clavate, colorless, 12.8-26.5 x 3.1-10.3 µm (av.= 19 ± 4.1 x 6.7 ± 2.2 µm, Q = 3 ± 0.84, n = 10). Lamellar trama hyphae parallel, broad and of equal width throughout, 58.6-113 x 6.2-23.5 µm (n = 6). Pileipellis a cutis with the subpellis intergrading imperceptively with the pileus trama; yellowish-brown cytoplasmic pigment uniformly distributed in the subpellis, not encrusting, pigment lacking in suprapellis; end cells short, cylindroclavate. Pileus trama hyphae 66.1-92.9 x 10.4-16.2 µm (n = 5). Stipitipellis a cutis with a yellowish-brown cytoplasmic pigment; hymenial clusters and caulocystidia absent. Refractive hyphae scattered in the trama of the pileus and stipe, sinuous and narrow. Clamp connections small and inconspicuous, present on the hyphae of lamellar trama and pileipellis and at the base of the hymenial elements and cheilocystidia; absent on stipitipellis.
Habit, habitat and distribution. - Solitary on shallow, gray sand soil in leguminous forest dominated by Aldina insignis; known only from the type locality.
Etymology. - Rugosus, striatus, Latin; referring to the rugose pileus with translucent-striate margin.
Specimens examined. - Guyana. Region 8 Potaro-Siparuni: Pakaraima Mountains, Upper Ireng River Basin; 3 km downstream from Kurutuik Falls, elevation ~800 m, under A. insignis, 25 May 1998, Henkel 6766 (Holotype: BRG; Isotype: HSU; MycoBank No. MB 510896).
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