Agaricales » Crepidotaceae » Crepidotus

Crepidotus ungulatus

Crepidotus ungulatus Phonemany, Thongkl. & Sysouph.

Faces of fungi number: FoF 150102, MycoBank: MB 850910

Basidiomata pleurotoid, small. Pileus 10–15 × 10–20 mm; ungulate to spathulate, with inflexed margin to involute margin; white when young, brownish orange (5C4–5, 5D5) near point of attachment, becoming light brown when mature (5D4–5); smooth, hygrophanous, covered with white woolly hyphae in the attachment zone; margin sulcate-striate, concolorous to the pileus surface. Lamellae up to 1 mm wide, decurrent, white when young, becoming pale yellow to yellowish (4A3–4A2), finally light brown (5D4–5), moderately crowded, with 4–5 tiers of lamellulae, with smooth edge. Stipe absent or pseudostipe, very short. Context is very thin, soft, and white. Odor none, taste none. Spore prints brown (6D6, 6E6).

Basidiospores [150/3/2] (5.5–)5.5–6–10.7(–11.2) × (4–)4–4.5–5.2(–5.4) µm, Q = (1.19–)1.25–1.51–2.56(–2.64), broadly ellipsoid to elongate, buff yellow to light orange-yellow in KOH and water, smooth, thick-walled. Basidia (12.1–)12.1–16.0–20.1(–20.6) × (4.8–)4.9–6.0–7.8(–7.8) µm, subclavate to clavate, 4-spored, sterigma 5–7 µm long, hyaline, smooth, thin-walled. Cheilocystidia (15.6–)15.6–28.3–75.3(–75.8) × (5–)5.2–9.5–23.7(–23.7) µm, narrowly lecythiform, lecythiform to sublecythiform with subcapitate at apex, hyaline, smooth, thin-walled. Pleurocystidia absent. Hymenophoral trama irregular, cylindrical hyphae 3–9 µm wide. Pileipellis a cutis composed of parallel hyphae 3–8 µm wide, hyaline, with cylindrical terminal elements 45.0–66.8 × 8.4–11.2 µm. Oleiferous hyphae absent. Clamp connections are present in all structures.

Habitat and distribution: — Saprobic on the dead branch, scattered with at least 10 basidiomata. This has only been found in northern Thailand.

Additional specimens examined: — THAILAND. Chiang Mai Province, Mae Taeng District, Pang Hang Village, 19°07'44.8"N, 98°45'47.8"E, 15 July 2020, Monthien Phonemany (MFLU23-0430).

Notes: — Crepidotus ungulatus has the main characteristic of ungulate basidiomata, brownish orange near the point of attachment, the basidiomata colour changed to light brown in 3 hours, and the margin concolorous to the surface of the pileus. The available description of Crepidotus species, most similar to C. ungulatus was C. applanatus (Pers.) P. Kumm. But the morphology comparison found that C. applanatus had planoconvex to applanate, flat, and larger basidiomata (5–40 × 5–50 mm), stipe cylindrical whitish, with pubescent, larger basidia (13–19.4 × 5–6.6 µm), and smaller cheilocystidia (28.8–40.9 × 8.1–11.9 µm) (Jančovičová et al. 2022).

In the phylogenic tree of the species, the most closely related to C. ungulatus (MFLU23-0429) was C. striatus (HMJAU37087). However, total morphological differences such as C. striatus have basidiomata, margin reflexed when old, lamellae edge gelatinous, pileipellis a cutis with pileocystidia-like terminal elements(Ge & Bau 2020).