Conocybe mesospora
Year: 2026
Type: article
Abstract: Conocybe mesospora OTU 21 (according to International Conocybe consortium, unpubl.) Figs 2 A – C, 3 A, 3 B, 4, 5 Description. Basidiomata mycenoid. Pileus 5–15 mm diam, initially paraboloid to obtusely conical, later broadly conical, subumbonate, margin aspects straight, undulate. At the young stage, the center ranges from red-orange (RAL 2001) to traffic orange (RAL 2009) and bright red-orange (RAL 2008), while the margin varies from saffron yellow (RAL 1017) to pastel yellow (RAL 1034) and ochre brown (RAL 8001), the colors become darker, with the pileus center changing from red-brown (RAL 8012) to pearl orange (RAL 2013), and the margin transitioning from pastel yellow (RAL 1034) to ochre brown (RAL 8001) at maturity. Hygrophanous, smooth, slightly viscid, pubescent, striate up to half center. Context thin, pastel yellow (RAL 1034) to ochre brown (RAL 8001), no distinct odor or taste. Lamellae adnexed to narrowly adnate, ventricose, moderately crowded, unequal, sand yellow (RAL 1002) to ivory (RAL 1014), pastel yellow (RAL 1034), margin even to slightly eroded. Stipe 15–25 mm long, 1–2 mm thick, cylindrical, light ivory (RAL 1015) to ivory (RAL 1014), surface pruinose and pubescent, with longitudinal fibrillose striate, base subbulbous. Basidiospores (60 / 3 / 3) (6.8 –) 7.3–8.3 (– 8.7) × 3.8–4.7 μm, Q = (1.65 –) 1.69–2.02 (– 2.1), Q m = 1.82 (± 0.09), non-lentiform, oblong to subcylindrical, slightly amygdaliform, thick walled, containing oil droplets, germ pore approximately 1–2 μm in diameter, ochre brown (RAL 8001) to clay brown (RAL 8003) in KOH solution. Basidia (19 –) 21–29 (– 30) × 7–9 μm, narrowly clavate to clavate, 4 - spored, sterigmata 2–5 μm long, vacuolar contents present. Cheilocystidia 15–20 (– 23) × (6 –) 7–11 μm, lecythiform (body lageniform, broadly ellipsoid to oblong, some subglobose), with capitula 3–4 μm wide. Pleurocystidia absent. Caulocystidia (16 –) 18–26 (– 29) × (7 –) 8–13 μm, predominantly lecythiform (ca. 90 %, body lageniform, broadly ellipsoid to oblong, some subglobose), capitula 3–6 μm wide, intermixed with clavate, subglobose and subellipsoid elements. Pileipellis epithelioid hymeniderm, composed of spheropedunculate and clavate cells (27 –) 29–43 (– 45) × (10 –) 12–18 μm, basal region with fawn brown (RAL 8007) pigment. Pileocystidia (25 –) 26–34 (– 38) × (6 –) 7–12 μm, lecythiform to tibiiform (ca. 90 %, body lageniform, broadly ellipsoid to oblong), capitula 3–5 μm wide, some pigmented in water and KOH solution, occasionally with filamentous elements. All structures with clamp connections. Negative reaction with ammonia. Habitat. The specimens collected in this study grow solitary or gregarious on the humus layer near Sambucus williamsii Hance during summer and autumn. Known distribution. Jilin Province, Siping City, China. Additional collection examined. China • Jilin Province, Siping City, Yitong Manchu Autonomous County, 18 August 2025, 43°36'00"N, 125°12'11"E, alt. 369 m, L. J. Zhao, S 25081913 (FJAU 78846), S 25081914 (FJAU 78847). China • Jilin Province, Siping City, Yitong Manchu Autonomous County, 23 August 2025, 43°36'00"N, 125°12'11"E, alt. 369 m, H. B. Song S 25082309 (FJAU 78848). China • Jilin Province, Siping City, Yitong Manchu Autonomous County, 25 August 2025, 43°35'54"N, 125°12'11"E, alt. 387 m, H. B. Song S 25082519 (FJAU 78849). China • Jilin Province, Siping City, Yitong Manchu Autonomous County, 29 September 2025, 43°35'17"N, 125°11'57"E, alt. 457 m, H. B. Song S 25092901 (FJAU 78850), S 25092903 (FJAU 78851). Sequences were obtained from all specimens mentioned above, and their morphology was also examined. Notes. The description of Conocybe mesospora OTU 21 was originally intended to clarify the phylogenetic position of C. mesospora. However, C. mesospora lacks a type sequence, and available non-type sequences are polyphyletic (C. mesospora IBL 6 and C. mesospora GLM 45895) and in at least three different clades (located in sect. Conocybe Clade 1 and Clade 2). Morphological evidence alone is insufficient to support a definite taxonomic conclusion, and the sequence of the material is within the C. mesospora OTU 21 of the International Conocybe consortium (unpubl.). To decide which one of the currently differentiated OTUs is in accordance with the type of C. mesospora will require sequences obtained from the French type material (Singer and Hausknecht 1992; Hausknecht 2009).
Institution: Dali University
Language: English
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7204239616