taxonID	type	description	language	source
2418D75FFFFEFF80FF69F99EFAD3B430.taxon	diagnosis	Diagnosis: Russula lilliputia is characterized by the remarkably small size of its red pileus not exceeding 5 mm, its densely pruinose stipe, and pileus when dry, its restricted distribution in Guyana and basidiome production on the surface of trunks of Dicymbe altsonii trees, spores with relatively indistinct suprahilar plage and occasional scarce, low interconnections between verrucae, long hairlike pileocystidia arising from an epithelioid layer of swollen cells, and white spore print. Etymology: in reference to the diminutive size of the basidiomata – these mushrooms could easily have been part of the mushroom flora of Lilliput encountered in Swift’s Gulliver’s Travels. Holotype: GUYANA. Region 8 Potaro – Siparuni. Pakaraima Mountains, Upper Potaro River Basin, within 15 km radius of Potaro base camp located at 5 ° 18 ʹ 04.8 ʺN 59 ° 54 ʹ 40.4 ʺW, 710 – 750 m; 23 May 2000, S. L. Miller 10046 (holotype BRG; isotype RMS). GenBank ITS PP 741561. Macroscopic description: — Pileus 3 – 5 mm broad, convex young, then broadly convex, plane or slightly depressed; margin incurved at first, then decurved, entire when young, then frequently lacerate with age, not striate young, sulcate striate when older, striations 1 – 2 mm in length; pellis dry to moist, pruinose at margin when young, subvelutinous to scurfy in age, disk of primordia pale red to pastel red (9 A 3 – 4) with white margin, then brownish red (9 C – 6 – 8) overall or with center of disk reddish brown (9 E – 6 – 8; 9 F 6 – 8), cuticle separability not determined. Lamellae 1 – 2 mm broad at mid-radius, sinuate, subdistant, not forking at stipe, lamellulae absent but occasionally anastomosing near the cuticle, margin entire, white. Stipe 7.5 – 10 × 2 – 3 mm, equal slightly tapered to base, terete to straight cylindrical to slightly curving, attachment central, dry, densely pruinose to subhispid overall, white (i. e., concolorous with lamellae); trama in stipe stuffed, soft. Context in pileus 1 mm at mid-radius soft and pliant, white. Odor not detected. Taste mild, fungal. FeSO 4 yellow on stipe surface. Spore print white. Microscopic description: — Basidiospores 6.8 – 8 × 6.4 – 7.2 µm, (x = 7.4 x 6.8 µm, Q = 1.06 – 1.11, Q m, = 1.0), subglobose to broadly ellipsoid; ornamentation of widely distributed, mostly isolated, acute, narrowly conical elements that are occasionally broader at the base, 1.5 (– 2) μm high, with scarce low connections, amyloid; suprahilar plage large and verruculose, not decurrent on the apiculus. Basidia (24) 27 – 29 (– 36) × 8 – 11 (13) μm, clavate to subcylindrical, 4 - spored, sterigmata long, 8 – 12 × 1.6 – 2 μm. Hymenial cystidia 43 – 60 × 10 – 13 μm, subclavate to cylindrical, obtuse to capitate, thin-walled, some long, arising deep within the lamella trama, others shorter, arising in hymenium, emergent 10 – 35 μm above basidia, scattered to patchy (400 – 600 / mm 2), greyish black in SV. Marginal cells 85 – 90 × 15 – 20 μm, fusiform, mucronate, strongly emergent, mixing with small basidia, numerous. Subhymenium well developed of small tightly packed spherical cells of 10 μm diam Lamellar trama composed of many large sphaerocytes, and nests of relatively small, nearly isodiametrical sphaerocytes, interwoven with cylindrical hyphae. Pileipellis orthochromatic in Cresyl Blue, two-layered; subpellis of slightly gelatinized interwoven hyphae of 4 – 5 μm diam intergrading with discrete regularly spaced rosettes, these often encrusted with reddish brown pigment in KOH; suprapellis arranged in a loose trichoderm from pileus center to pileus margin, composed of frequently branching spindly, digitate hyphae, 5 – 12 μm diam, cylindrical to clavate, obtuse or capitate and often sinuous and irregularly constricted, often multi-septate, thin- or moderately thickened walls, arising from large inflated, ellipsoidal to spherical cells, 20 – 35 × 8 – 20 µm, 2 – 6 deep in aggregate resembling an epithelium, these easily disarticulated in microscopic preparations; Pileocystidia 50 – 100 μm, long pedicellate, septate, irregularly constricted or swollen at the septum, banded with refringent contents particularly near the septa, moderately thick-walled, arising deep in the trama, SV – or turning pale grey, the contents or interior of the walls acid resistant in BF, no incrustations were observed. Stipitipellis resembling the pileipellis but lacking the swollen elements, composed of dense clusters of long branching, septate, digitate or slightly capitate to irregularly shaped hyphae, and pedicellate, septate, thick-walled caulocystidia that are cylindrical, clavate, obtuse and irregularly constricted. Habit, habitat, and distribution: — Scattered across the trunk surface 1.5 m above the base of a Dicymbe altsonii Sandwith tree. Known only from a single large collection, Upper Potaro Basin of Guyana. We feel confident for several reasons in describing R. lilliputia as a new taxon from a single collection. The type collection was comprised of all stages of basidiome development which included approximately thirty individual basidiomata and primordia distributed across a half-meter-square area of trunk surface 1.5 m above the base of a Dicymbe altsonii tree. The primordia were more numerous than the expanded basidiomata, and the largest basidiomata were never observed to be larger than 5 mm in diameter before beginning to senesce. Importantly, all of the largest basidiomata produced an easily observable white spore print on an acetate sheet, indicating that the basidiomata were mature and not just slightly expanded primordia. BLAST similarity searches on GenBank recovered no close matches. Further, our ITS analyses (not all of which are shown), including all of the red, reddish, or reddish orange Russula collections from our collecting sites in Guyana, along with another newly described red species, R. rubroglutinata S. L. Mill, T. W. Henkel & Aime, ined., included in the present analysis, indicated that R. lilliputia is distinct.	en	Miller, Steven L., Aime, M. Catherine, Henkel, Terry W. (2024): Russulaceae of the Pakaraima Mountains of Guyana 5. Two newly described diminutive species in a novel lineage of the crown clade of Russula (Russulaceae). Phytotaxa 668 (2): 117-129, DOI: 10.11646/phytotaxa.668.2.1, URL: https://doi.org/10.11646/phytotaxa.668.2.1
2418D75FFFFAFF8EFF69FB60FC5BB50C.taxon	diagnosis	Diagnosis: Russula pakaraimaeae is characterized by its small stature (pileus 5 – 17 (25) mm), its occurrence in the Upper Mazaruni Basin of Guyana in fringe forests surrounding the Pegaima savanna in association with Pakaraimaea dipterocarpaceae and possibly Dicymbe jenmanii, by its fruiting habit with branching or single rhizoidal base attached to large fallen leaves and organic debris, by its dark red to brownish violet pileus with pruinose white margin when young, stipe viscid in wet conditions wet then with appressed fibrillose squamules often flushed pinkish when conditions are dry, spores of isolated verrucae with no interconnections and a distinct suprahilar plage that occasionally forms a partial collar on the apiculus, by its long hairlike pileocystidia arising from scattered swollen cells. Etymology: in reference to the occurrence in forests fringing savanna dominated by Pakaraimaea dipterocarpacea (Cistaceae). Holotype: GUYANA. Pakaraima Mountains, Upper Mazaruni River Basin, fringing forest around the Pegaima savanna, 0.5 km S of Pegaima base camp located at 5 ° 26 ′ 21.3 ′′ N; 60 ° 04 ′ 43.1 ″ W, ~ 800 m elevation; under Pakaraimaea dipterocarpacea and Dicymbe jenmanii, 21 December 2010, T. W. Henkel 9503 (holotype BRG; isotypes HSCF 004453, RMS). GenBank ITS KC 155378. Macroscopic description: — Pileus 5 – 17 (25) mm broad, first convex and sometimes mammilate, then broadly convex to slightly depressed, with or without umbo; margin decurved, entire but markedly pruinose when young, then frequently minutely lacerate or crenulate with age, smooth to obscurely striate when young, faintly plicate to subsulcate when older, striations 2 – 4 mm in length; pellis dull to shiny, heavily pruinose when young especially toward the margin, viscid when wet, subfloccose to subtomentose when dry, matted toward the margin, dark red (11 C 6 – 11 C 7) to brownish violet (11 D 7 – 8) to violet brown (11 F 7 – 8) with extreme margin white when young, then red to dark red or brownish red (10 B 7 – 10 D 7,8) when expanded, disk and umbo remaining violet brown (11 E 6 – 11 F 8). Lamellae 1 – 2 mm broad at mid-radius, adnate to slightly sinuate to subdecurrent, close to subdistant, entire, white when young, eventually pale yellow (3 A 2 – 3); lamellulae rare to absent. Stipe 14 – 33 (48) × 1.5 – 3 (5) mm, equal or more typically tapered to single or branching rhizoid-like base, attachment central, even to slightly irregular, flattening, canaliculate with age, pruinose above, middle portions with white to pink appressed fibrillose squamules, base subtomentose, white to cream (3 A 2 – 3) at apex (i. e. concolorous with lamellae, middle portions overlain with pale red areolae frequently in a stretch-mark like pattern over a white or yellowish white (3 A 2) ground; the base concolorous with the apex; viscid in wet conditions. Context in pileus 1 – 1.5 mm at mid-radius pliant, white, pale pink immediately below cuticle, especially at disk; trama in stipe stuffed at maturity, outer cylinder pale yellow surrounding white central core; odor mild; taste mild to faintly sweet or slightly bitter; FeSO 4 not noted. Microscopic description: — Basidiospores 7.2 – 8.8 × 5.8 – 7.04 (x = 7.96 × 6.4, Q = 1.25 – 1.3, Qm = 1.25), broadly ellipsoid; ornamentation of widely distributed, isolated, acute, narrowly conical elements, 1.5 – 2 (– 2.5) μm high, amyloid, darkest near the apiculus; suprahilar plage large and verruculose, not or forming a collar on the apiculus. Basidia 25 – 3 × 8 – 10 μm, subcylindrical to clavate, 4 - spored, sterigmata long, 6.4 – 10 × 1.5 – 1.9 μm. Hymenial cystidia 35 – 50 × 6 – 8 μm, cylindrical, subclavate to clavate, obtuse to capitate, or occasionally rostrate, mostly thin-walled, some thick-walled, some long, arising deep within the lamella trama, others shorter arising in hymenium, emergent 2 – 40 μm above basidia, scattered to numerous 800 - 1000 per mm 2, SV –. Marginal cells 45 – 75 × 7 – 13 μm, subclavate, fusiform, mucronate or irregular, strongly emergent, mixing with small basidia, moderately numerous. Subhymenium well developed of small tightly packed spherical cells of 10 μm diam. Lamellar trama composed of many large sphaerocytes, and nests of relatively small, nearly isodiametrical to globose sphaerocytes, interwoven with cylindrical hyphae. Pileipellis, two-layered; subpellis of slightly interwoven inflated to swollen hyphae of 6 – 15 μm diam; suprapellis arranged in a loose trichoderm from pileus center to pileus margin composed of infrequently branching spindly hyphae, 5 – 12 μm diam, cylindrical to clavate or digitate, obtuse or sinuous and irregularly constricted, often multi-septate, thin- or thick-walled, often arising from inflated cells; Pileocystidia 50 – 250 μm × 3 – 5 µm obtuse digitate or capitate, pedicellate, septate, irregularly constricted or swollen at the septum, banded with refringent contents particularly near the septa, thin-or thick-walled, arising deep in the trama but extending 120 – 160 µm above the surface of the pellis, these easily disarticulated in microscopic preparations, SV- to pale grey, orthochromatic in Cresyl Blue, the contents or interior of the walls acid resistant in BF, no incrustations were observed. Stipitipellis resembling the pileipellis, composed of branching, septate, irregularly shaped hyphae that taper at the apex, and long pedicellate, septate, thick-walled caulocystidia that are cylindrical, digitate, clavate, obtuse or capitate and irregularly constricted 50 – 250 µm. Habit, habitat, and distribution: — Solitary or in small troops in December on humic matter and large fallen leaves on forest floor in ECM P. dipterocarpacea / Dicymbe jenmanii savanna fringing forests, or in stands with only P. dipterocarpacea. Sequences corresponding to R. pakaraimaeae have also been found from the sampling of ectomycorrhizal roots at the Pegaima savanna (Smith et al. 2013). Known only from the type locality in the Upper Mazaruni Basin of Guyana. Additional specimens examined: — GUYANA. Pakaraima Mountains, Upper Mazaruni River Basin, fringing forest around the Pegaima savanna, within a 1.5 km radius of Pegaima base camp located at 5 ° 26 ′ 21.3 ′′ N; 60 ° 04 ′ 43.1 ″ W, ~ 800 m elevation; 0.1 km N of base camp in pure stand of Pakaraimaea dipterocarpacea, 22 December 2010, T. W. Henkel 9515 (BRG; HSCF 004454; RMS); 1.5 km SW of base camp in pure stand of Pakaraimaea dipterocarpacea, 26 December 2010, T. W. Henkel 9548 (BRG; HSCF 004455; RMS).	en	Miller, Steven L., Aime, M. Catherine, Henkel, Terry W. (2024): Russulaceae of the Pakaraima Mountains of Guyana 5. Two newly described diminutive species in a novel lineage of the crown clade of Russula (Russulaceae). Phytotaxa 668 (2): 117-129, DOI: 10.11646/phytotaxa.668.2.1, URL: https://doi.org/10.11646/phytotaxa.668.2.1
