Basidiomata small. Pileus 1–2 cm broad, convex to planoconvex, never depressed at centre; reddish brown (8E7) to dark brown (9F8) at centre, gradually paler towards margin; surface dry, tomentose to velutinous; context off-white to yellowish white, reddish brown under the pellis, unchanging. Hymenophore lamellate, decurrent; lamellae thick, distant, ventricose, some forking to intervenose, mostly near the margin, yellowish white (4A2) when young, in age deeper yellow, with a reddish tinge near the edge, sometimes with reddish dots, staining absent; lamellar edge even. Stipe 1.5–3 cm long, 0.2–0.3 cm wide, mostly equal; surface dry upper half finely pustulate, light brown (6D8) to cinnamon (6D6), consistently darker near apex; lower half glabrous to subglabrous, champagne (4A4) to yellowish white (4A2), staining absent; context solid, yellowish white (4A2), staining absent. Basal mycelium white, with fine white rhizoids. Macrochemical reactions: not recorded. Basidiospores [150/3/3] (7.9–)8.3–9.3–10.3(–11) × (4.1)4.2 4.7–5.2(–5.5) μm,, Q = (1.65–)1.78–1.99–2.21(–2.47), variable in shape, elliptical to subovoid, sometimes more fusoid, greenish grey (1C2) in 5% KOH, smooth under light microscope, but with bacillate ornamentation under SEM. Basidia (30–)30–35.2–42(–42) × (7.3–)7.3–8.8–10.7(–10.8) μm, clavate, hyaline, 4-spored. Cheilocystidia (57–)57–68–84(84) × (12.1–)12.1–15–18(–18) μm, utriform to sublageniform. Pleurocystidia (60.6–)60.6–75.2–93.1(–93.1) × (7.1–)7.2–13.6–18.2(–18.2) μm, numerous, subclavate to broadly clavate or utriform to sublageniform, without encrusting pigments. Hymenophoral trama 100–170 μm thick, regular, composed of 7–15 μm wide cylindrical, smooth, hyaline hyphae. Pileipellis an interwoven trichoderm; hyphae slightly constricted at septa; terminal cells 25–55 × 7–16 μm, cylindrical, granular content present and sometimes with cell wall encrustations (mostly on terminal cells) visible in aqueous Congo Red. Pileus trama hyaline, smooth hyphae 8–13 μm wide. Stipitipellis 75–100 μm thick, parallel hyphae and caulocystidia (18–)18–24.6–33(–33) × (7.1–)7.2–9.2–11.2(–11.4) μm, clavate to capitate, hyaline, smooth. Stipe trama composed of parallel, cylindrical, hyaline hyphae 7.5–15 μm wide. Clamp connections absent in all tissues. Habit, habitat and distribution: Solitary on litter-poor soil (e.g. path or road verges) in forests dominated by Fagaceae. Thailand and Yunnan province, China. (Figs. 1-2)
MycoBank number: MB 827266, Facesoffungi number: FoF 04842.
Etymology: pusillus refers to the (very) small size of the basidiomata.
Holotype: Thailand. Chiang Mai Province, Meuang District, Doi Suthep-Pui National Park, N18°48.6′– E98°53.5′, elev. 1450 m, 14/07/2016, O. Raspé, OR1310 (CMUB!, holotype; BR!, isotype).
Fig. 1 Basidiomata of Phylloporus pusillus (holotype, OR1310) in the field. a, b Photograph of basidiomata from upper and lower part. Scale bars = 1 cm.
Fig. 2 Micro-morphological characters of Phylloporus pusillus. a Basidiospores. b Basidia. c Cheilocystidia. d Pleurocystidia. e Pileipellis. f Stipitipellis. g Caulocystidia. Scale bars: a = 10 μm; b–d, g = 20 μm; e, f = 50 μm. All drawings were made from the type (OR1310)
Chuankid B, Vadthanarat S, Hyde KD, Thongklang N, Zhao R, Lumyong S and Raspé O 2019 – Three new Phylloporus species from tropical China and Thailand. Mycological Progress, 18(5), pp.603–614.