Cantonopsathyra serendipita Kun L. Yang, Jia Y. Lin, Zhen-Chao Liu & Zhu L. Yang, 2025

Yang, Kun L., Lin, Jia Y., Li, Guang-Mei & Yang, Zhu L., 2025, Introducing one new genus and two new species of Psathyrellaceae (Basidiomycota, Agaricales), with notes on Candolleomyces and Ephemerocybe, Phytotaxa 702 (1), pp. 1-28 : 11-12

(1.1) Cantonopsathyra serendipita Kun L. Yang, Jia Y. Lin, Zhen-Chao Liu & Zhu L. Yang , sp. nov.

( Fig. 5 )

Registration identifier:— FN572406

Etymology:— The holotype of this species is the first collection that the discoverer collected in her mycological career.

Diagnosis:— Similar to Cantonopsathyra malayana and Cn. trechispora , but differing from them by smaller basidiomata, smaller basidiospores, and the presence of pleurocystidia.

Type:— China, Guangdong Province, Guangzhou City, Tianhe District, Tianhe Park , 23°07’54”N, 113°21’37”E, elevation 50 m, May 1, 2023, Jia Y. Lin & Kun L. Yang, L2301 ( HKAS145964 , holotype (ITS: PV155171 ; nrLSU: PV147345 ; tef-1α: PV156691 ; β-tub: PV156729 ); HTBM0834 , isotype) .

Description:— Basidiomata psathyrelloid, small, fragile, not deliquescent nor collapsing. Pileus 19–46 mm in diameter, convex, plano-convex, applanate to plano-concave, more or less umbonate at center, slightly rugose, hygrophanous, ceramic white (#FEFEFA), garlic yellow (#F1F0D4), butter orange (#F2DF8F), rust orange (#D79A65) to mummy red (#994D2E), uniformly colored or becoming lighter towards margin, becoming pale after dried; veil absent; margin entire to more or less cracked, shortly to very shortly striate. Lamellae adnexed to emarginate, crowded, thatch yellow (#F1ECC5), dirty brass brown (#B47F5A) to chocolate brown (#86604B), with a serrate, pale edge, interspersed with abundant lamellulae. Stipe 26–100 mm long, 3.5–6 mm thick, cylindrical to subcylindrical, hollow, distinctly striate, ceramic white (#FEFEFA) to dirty brass brown (#B47F5A), with fibrous, ceramic white (#FEFEFA) squamules, without an annulus. Odor fungal. Taste fungal.

Basidiospores {40/3/3} 6.5–8.5 (9) [7.54 ± 0.75, 7.50] × (4) 4.5–5.5 [5.00 ± 0.42, 5.00] µm, Q = (1.27) 1.30–1.89 [1.51 ± 0.16, 1.45] including myxosporial ornamentation around 0.5 µm high, broadly fusiform, thick-walled or slightly thick-walled, brownish in both water and 5% KOH, with an irregularly wrinkled surface, a small apiculus and a central germ pore. Basidia 26–33 × 9–10.5 μm, clavate, mostly four-spored, rarely two-spored, thin-walled, nearly colorless, with sterigmata up to 4 µm long, surrounding by basidioles 12–28 × 7–10 μm. Hymenial physalides poorly developed. Lamella trama regular, composed of 4–10 µm wide, thick-walled or slightly thick-walled, slightly brownish, compact, rarely to moderately branching hyphae. Cheilocystidia very abundant, 25–55 × 9.5–19 µm, mostly clavate, rarely utriform, thin-walled to slightly thick-walled, smooth, very slightly brownish. Pleurocystidia rare, 35–58 × 16–24 µm, sphaeropedunculate to clavate, thin-walled, smooth, nearly colorless. Pileipellis hymeniform, composed of thick-walled or slightly thick-walled, clavate terminal cells measured 25–36 × 10–14.5 µm, brownish. Clamp connections occasionally present in pileus context, absent elsewhere.

Habits and distribution:— Gregarious, on soil, in subtropical forests. Currently known from South China.

Other collections examined:— China, Guangdong Province, Guangzhou City, Huangpu District, Jiangdong Village , Boluoshan Hill , 23°11’36”N, 113°32’25”E, elevation 150 m, July 30, 2023, Zhen-Chao Liu & Jia Y. Lin: L23224 ( HTBM1176 ) and L23225 ( HTBM1177 ) ; same location, August 25, 2023, Zhen-Chao Liu, Jia Y. Lin & Kun L. Yang: S23515 ( HTBM1626 ). China, Guangdong Province, Guangzhou City, Tianhe District , Furnace Mountain (Huolushan) Forest Park , 23°11’07”N, 113°23’05”E, elevation 200 m, June 6, 2023, Jia Y. Lin, Kun L. Yang & Zhe Er Gen: L24126 ( HTBM2013 ), L24127 ( HTBM2014 ), L24128 ( HTBM2015 ) and L24129 ( HTBM2016 ) .

Figures

FIGURE 5. Cantonopsathyra serendipita (photos by Jia Y. Lin, Kun L. Yang & Zhen-Chao Liu, drawings by Kun L. Yang from HKAS145964 (holotype)). a–g. Basidiomata (a. HKAS145964 (holotype); b. HTBM2013; c. HTBM2016; d–e. HTBM2014; f. HTBM1176; g. HTBM1177). h–j. Basidiospores from HKAS145964 (holotype) (h. ventral view observed with LM, a same spore in two focusing surfaces; i. top view under SEM; j. dorsal view and subdorsal view under SEM). k. Cheilocystidia. l. Hymenium, subhymenium, and lamella trama, including a pleurocystidium. Bars: a = 2 cm, e = 1 cm, j = 5 µm, k–l = 10 µm.