Crepidotus chiangraiensis Phonemany, thongkl. & Sysouph

Phonemany, Monthien, Sysouphanthong, Phonguen & Thongklang, Naritsada, 2024, Additions to Crepidotus species (Basidiomycota): Six new species and two new records from Thailand, Phytotaxa 646 (2), pp. 91-115 : 98

Crepidotus chiangraiensis Phonemany, thongkl. & Sysouph ., sp. nov. ( Figures 2–3 )

Faces of fungi number: FoF 15096, MycoBank: MB 850908.

Etymology:— Chiangraiensis refers to the “ Chiang Rai Province ” where the holotype was collected.

Holotype:— THAILAND, Chiang Rai Province, Mae Fah Luang District, Mae Sa Long Nok Subdistrict , 20°10’10.9”N, 99°37’21.5”E, 14 June 2019, Monthien Phonemany ( MFLU23-0438 ).

Diagnosis:—This species is recognized by white to pale yellow small basidiomata velutinous pileus with white hairs, short stipe, subglobose to oblong obovoid basidiospores, utriform to sublecythiform with subcapitate at the apex, without pleurocytidia, regular hymenophoral trama, trichodermal pileipellis, and presence of clamp-connections.

Description: Basidiomata pleurotoid, small. Pileus 35–45 × 20–40 mm; orbicular, rounded flabelliform, with an involute margin when young and becoming straight when mature; white, becoming yellowish white (4A2) to pale yellow (4A3); densely velutinous with white hairs longer near the attachment zone, not hygrophanous, covered with white woolly hyphae at the attachment zone; margin wavy, split when mature. Lamellae 1 mm wide, adnexed, white when young, then pale yellow (4A3) to yellowish white (4A2) near the point of attachment, with dark brown spots on the surface of the lamellae, becoming brown (6D6) when fully mature, with 4 tiers of lamellulae, with smooth edge, moderately crowded. Stipe 1 mm wide, present in primordial stages, equal, white, rudimentary when mature, knobliked. Context very thin, white. Odor mild. Taste none. Spore print brown (6D6).

Basidiospores [150/3/2] (6.1–)6.6–8.1–9.6(–9.6) × (4.8–)5.3–6.2–7.5(–7.7) µm, Q = (1.08–)1.13–1.3–1.59(–1.85), subglobose to obovoid, buff yellow (5A3) to light yellowish brown (8D5) in KOH and water, smooth, thick-walled. Basidia (14.1–)14.2–16–18.4(–18.4) × (5.2–)5.2–6.5–7.4(–7.4) µm, clavate to subcylindrical, 4-spored, hyaline, smooth, thin-walled. Cheilocystidia (22.5–)22.5–36.4–61.3(–61.3) × (6.2–)6.2–11.8–25(–25) µm, various in shape, narrowly utriform to utriform, fusiform, lecythiform to sublecythiform, with subcapitate at apex, hyaline, smooth, thin-walled. Pleurocystidia absent. Hymenophoral trama regular, hyphae 2–5 µm wide. Pileipellis, a trichoderm composed of parallel hyphae with 2–5 µm wide, branched, hyaline, with cylindrical terminal elements 45.6–90.54 × 5.15–7.08 µm. Oleiferous hyphae 2–4 µm present in hymenophoral trama. Clamp connections present in all the structures.

Habitat and distribution:—Saprobic on a dead branch of an unidentified tree, scattered or gregarious with at least 10 basidiomata. So far, it has only been found in northern Thailand.

Additional specimens examined:— THAILAND. Chiang Rai Province, Mae Fah Luang District, Mae Sa long Nok Subdistrict, Mae Toe village, 20°10’27.7”N, 99°36’51.9”E, 14 June 2019, Monthien Phonemany (MFLU23-0439).

Figures

FIGURE 2. Basidiomata of Crepidotus chiangraiensis in the field.A–b MFLU23-0437, c–d MFLU23-0438. Scale bar a–d = 10 mm.

FIGURE 3. Micromorphology of Crepidotus chiangraiensis a Basidia, b Basidiospores, c Cheilocystidia, d Pileipellis. Scale bar a–b = 10 µm, c = 20 µm, d = 50 µm.