Agaricales » Crepidotaceae » Crepidotus

Crepidotus flavocarpus

Crepidotus flavocarpus Phonemany, Thongkl. & Sysouph.

Faces of fungi number: FoF 15097, MycoBank: MB 850911

Basidiomata pleurotoid, small. Pileus 10–30 × 9–25 mm; ungulate to spathuliform when primordial stages, becoming petaloid to rounded flabelliform expanding to dimidiate, sometimes convex, plano-convex when mature, with an incurved margin when young and becoming straight when mature; yellow to yellowish, light yellow, pastel yellow, pale yellow becoming yellowish white then brownish grey to greyish brown when old (3B7–8, 3A2–5, 5D2–3); covered with densely velutinous at the point of attachment, with white hairs in the attachment zone and sparse toward the margin, disappearing when old, hygrophanous; margin with short striate or sulcate, concolorous with surface to paler yellow at first, then white to brownish when old. Lamellae 2–3 mm wide, adnexed to sinuate, pale yellow, pastel yellow to white (3A2–3, 3A1), becoming dark brown spots on the surface of the lamellae when mature, distant, with 34 tiers of lamellulae, with smooth edge. Stipe absent. Context very thin, white to translucent when old. Odour and taste indistinct, mild. Spores print brown (6D6, 6E6).

Basidiospores [150/3/3] (5.5–)5.6–6.8.–7.6(–7.8) × (4.1–)4.3–5.5–6.5(–6.6) µm, Q = (1.01–)1.03–1.25–1.47(–1.53), globose to subglobose, yellowish brown (5D5–6), smooth, thick-walled. Basidia (14.8)14.8–18.7–21.2(–21.2) × (5–)5–6.9–8.1(–8.2) µm, subclavate, 4-spored, hyaline, smooth, thin-walled. Cheilocystidia (18.3)18.9–34.2–52.1(–55.9) × (4.1–)4.1–5.2–7.4(–7.8) µm, subcylindrical, narrowly utriform to sublecythiform, with subcapitate at apex, hyaline, smooth, thin-walled. Pleurocystidia absent. Hymenophoral trama inverse, hyphae 3–5 µm, with cylindrical terminal elements (17.1)18.8–25.1–30.6(–31.1) × (4.3–)4.4–5.5–6.7(–6.8) µm, hyaline, thin-walled. Pileipellis a cutis, hyaline to pale yellow, with cylindrical terminal elements 35–80 × 4–8 µm. Clamp connections present in pileipellis and hymenophoral trama.

Habitat and distribution: — Saprobic on dead wood, scattered by 2–3 basidiomata. So far only found in tropical forests in northern Thailand.

Additional specimens examined: — THAILAND, Chiang Mai Province, Mae on district, mountain behind Thangthong lodge, 25 June 2020, Monthien Phonemany (MFLU23-0428).

Notes: — The basidiomata colour of C. flavocarpus is similar to that of C. croceotinctus Peck, C. cristatus Senn-Irlet & Immerzeel, and C. parietalis E. Horak, C. praecipuus E.Horak, C. tobolensis Kapitonov, Biketova & Zmitr., C. yuanchui Q. Na, Z.W. Liu & Y.P. Ge. Those species have a colour pattern of yellowish, pale yellow, deep orange, to brownish-orange pileus. However, C. croceotinctus different from C. flavocarpus by having margin non-striate, larger basidiospores (7–8 × 5.5–6.5), vesiculose clavate cheilocystidia (Kumar et al. 2020). Crepidotus cristatus described in the Netherlands differs in having smaller basidiomata (2–10 mm), not hygrophanus, punctate warty, verruculose basidiospore (Senn-Irlet & Immerzeel 2003). The description of C. parietalis from New Zealand differs by having a longer striate margin, smaller basidiospores (5–6.5 µm long), larger cheilocystidia (20–40 × 5–8 µm), with pileipellis trichoderm (Horak 1977). Crepidotus praecipuus described from Korea differs by having minutely tomentose-scaly with yellowish-brown to brown fibrillose scales, basidiospores ellipsoid (Kim et al. 2021). Crepidotus yuanchui described in China differs in having a wavy margin without sulcate, villose with white hairs, and smaller basidiospores (5–6 × 4.2–5.2 µm) (Na et al. 2022). Crepidotus tobolensis described from Siberia differs by having surface matt, tomentose, non-squamulose, basidiospores broadly-lacrymoid (Malysheva et al. 2022). Phylogenetically, C. flavocarpus (MFLU23-0427) was closely related to C. alabamensis (TBGT15610) and C. albolanatus (PDD:72865) with (86% BS, and low supported for Bayesian analysis). Moreover, the morphologies of both species are completely different, with C. alabamensis having smaller basidiomata (3–20 mm), lamellae radiating from a lateral point, and smaller cheilocystidia (17.5–40 × 5–10.5 µm) (Kumar et al. 2022). C. albolanatus differs by having pure white pileus, with larger basidiomata of 10 to 35 mm (Horak  2018).