Crinipellis siamensis Kumla & N. Suwannar., 2024

Kumla, Jaturong, Phonrob, Wiphawanee, Lumyong, Saisamorn & Suwannarach, Nakarin, 2024, Crinipellis siamensis (Marasmiaceae, Agaricales), a new macrofungus from northern Thailand, Phytotaxa 666 (2), pp. 135-145 : 140-141

Crinipellis siamensis Kumla & N. Suwannar. sp. nov. ( Figures 2 and 3 )

MycoBank number: MB 854688

Diagnosis:—Distinguished from C. trichialis by its narrower size of elongate to cylindrical basidiospores and absence of appendages on cheilocystidia.

Etymology:— ‘ siamensis ’ refers to the former name of the country “ Thailand ” where the holotype was collected.

Holotype: — THAILAND, Chiang Mai Province, Muang District, Chiang Mai University , 18°47´49´´N 98°57´38´´E, elevation 329 m, on a bark of a living stem of Pterocarpus macrocarpus , 17 August 2022, J. Kumla & N. Suwannarach, CMUB40060 .

Gene sequences (from holotype):—PP992079 (ITS) and PP992082 (nrLSU).

Description:— Pileus 15–28 mm, almost hemisphaerical when young, then convex to plano-convex with abrupt papilla sometimes with acute papilla, inflexed to involute, margin fibrillose, central zone dark brown (6F6–7F8), middle zone brown (6E6–7E8), grayish orange, brownish orange to brown (6B6–6D7). Lamellae close, 1–2 lamellulae tiers, adnexed to free, white to orange white (5A1–5A2), with concolorous, entire. Stipe 23–58 × 1–2.5 mm, cylindrical, dark brown at base paler toward apex (8F6–6C4), densely hairy with orange-brown hairs like pileus. Rhizomorphs absent.

Basidiospores (150/5/2) 8.5–10.0 × 4.5–5.0 μm, average 9.4 × 4.7 μm, Q = 1.80 2.20, Q m = 2.00±0.21, elongate to cylindrical, thin-walled, smooth, hyaline, inamyloid. Basidia 19–23 × 5–7 μm, clavate, 4-spored. Pleurocystidia 34–48 × 3–7 μm, thin-walled, narrowly subcylindrical to lageniform. Cheilocystidia abundant, 32–45 × 3–5 μm, thin-walled, narrowly calvate to subcylindrical with rounded to acute apex. Pileipellis a cutis composed of cylindrical, thick-walled hyphae, dextrinoid, up to 10.0 μm wide hyphae. Pileus hairs 45–250 × 4–6 μm, cylindrical, thick-walled (walls up to 2.0 μm), acute to subacute, septate, dextrinoid, yellowish-brown to greenish brown in 5 % KOH. Stipitipellis a cutis of cylindrical, parallel, slightly thick-walled, dextrinoid, up to 6.0 μm wide hyphae. Stipe hairs similar to pileus ones, but shorter, 45–100 × 10–12 μm, dextrinoid, yellowish brown to greenish brown in 5% KOH. Clamp connections present in all tissues.

Ecology and distribution:—Fruiting solitary or gregarious on a bark of a living stem of Pterocarpus macrocarpus . Known only from the type locality in northern Thailand.

Additional specimens examined:— THAILAND, Chiang Mai Province, Muang District, Chiang Mai University, 18°47´48´´N 98°57´38´´E, elevation 329 m, on a bark of a living stem of Pterocarpus macrocarpus , 9 August 2023, J. Kumla & N. Suwannarach, SDBR-CMUNK1898, gene sequences PP992079 (ITS) and PP992201 (nrLSU).

Notes:—Morphologically, C. siamensis resembles C. scabella , C. trichialis , and C. zonata in terms of pileus color. However, the larger basidiospores in C. siamensis (8.5–10.0 × 4.5–5.0 μm) distinguish it from C. scabella (6.0–7.5 × 4.0 μm) ( Murrill 1915). The narrower size range of elongate to cylindrical basidiospores in C. siamensis can differentiate it from C. trichialis (6–11 × 5–8 μm) ( Kerekes & Desjardin 2009). Crinipellis zonata differs from C. siamensis due to its shorter basidiospores (5.0–8.0 × 3.0–5.0 μm) and the absence of pleurocystidia ( Singer 1943, Redhead 1989, Antonín et al. 2009). Additionally, the absence of appendages on cheilocystidia in C. siamensis clearly distinguishes it from C. trichialis and C. zonata ( Kerekes & Desjardin 2009, Antonín et al. 2009). Phylogenetically, C. siamensis forms a monophyletic clade with other Crinipellis species, but is well separated from other known Crinipellis species, including C. scabella , C. trichialis , and C. zonata ( Figure 1 ).

Figures

FIGURE 1. Phylogram derived from maximum likelihood analysis of 57 sequences of the combined ITS and nrLSU genes. Sequences of Marasmius brunneolorobustus BRI AQ1018016 and M. margallensis LAH 37597 were used as outgroups. The numbers above the branches represent maximum likelihood bootstrap percentages (left) and Bayesian posterior probabilities (right). Bootstrap values ≥ 75% and Bayesian posterior probabilities ≥ 0.90 are shown. The scale bar represents the expected number of nucleotide substitutions per site. Sequences of specimen vouchers obtained in this study are in red. Type species are in bold.

FIGURE 2. Basidiomata of Crinipellis siamensis. A. CMUB40060 (holotype) and B. SDBR-CMUNK1898. Scale bars: A and B = 10 mm.

FIGURE 3. Microscopic structures of Crinipellis siamensis CMUB40060 (holotype).A. Basidiospores; B Basidia; C. Pleurocystidia; D. Cheilocystidia; E. Pileipellis; F. Pileus hairs and G. Stipitipellis. Scale bars:A and E = 10 μm; B, C, D, F, and G = 5 μm.