INTRODUCTION

Macrofungi play important roles in natural ecosystems, adopting saprophytic, parasitic, and symbiotic lifestyle. They encompass ascomycetes and basidiomycetes, which are characterized by conspicuous sporebearing structures that are easily observable [1]. While the worldwide compilation of macrofungi names by the Index fungorum exceeds 20,000, the recorded macrofungi species in Korea amount to approximately 2,100. Among these, 1,800 species were basidiomycetes fungi and 290 species were ascomycetes fungi [2].

In this study, we conducted taxonomic research on the diversity of wild macrofungi in the forests of South Korea. Four previously unrecorded macrofungal species were collected in 2022. Based on taxonomic identification (morphological features and DNA fungal barcodes), two basidiomycete fungi (Laccaria striatula and Xerula strigosa) and two ascomycete fungi (Leotia atrovirens and Malvipezia emileia) were confirmed. Among these, Malvipezia was discovered to be an unknown genus in South Korea.

Four samples were collected during a mycological survey conducted in 2022 to investigate the mushroom diversity. In this study, these collections were examined for morphological identification based on their macroscopic and microscopic characteristics. The dried materials were mounted in distilled water and 5% KOH using a Zeiss Axio Imager A1 microscope (Jena, Germany) and an Axiocam 503 color camera (Jena, Germany). The taxonomic classification of the studied taxa followed the guidelines provided by the Index Fungorum (http://www.indexfungorum.org). Dried specimens were archived at the herbarium of the National Institute of Biological Resources (NIBR), Incheon, South Korea.

Table

Table

As a result, the ITS sequences were subjected to an RaxML analysis, resulting in the resolution of the phylogenetic positions of four species (Laccaria striatula, Leotia atrovirens, Malvipezia emileia, Xerula strigosa) (Figs. 1-4). Each species formed well-supported clades in their respective phylogenetic trees. In Laccaria phylogeny (Fig. 1), the Korean collection grouped together with L. striatula. Within the L. striatula clade, this species exhibited three distinct groups, indicating the presence of a species complex, based on ITS sequences. Further studies are required to validate the phylogenetic position of L. striatula. Regarding the Leotia phylogeny (Fig. 2), the Korean specimen was clustered with L. atrovirens group. Based on the phylogenetic analysis, the Korean collection was conclusively identified as L. atrovirens. In Malvipezia phylogeny (Fig. 3), the Korean collection clustered with M. emileia (KJ728715-KJ728717) with 100% BS values. Thus, the phylogenetic tree we constructed was supported by the position of M. emileia. In Xerula phylogeny (Fig. 4), X. strigosa clade was split into two groups. The Korean specimens clustered with X. strigosa from China (KF530556), with 100% BS values. Further studies are required to confirm this differentiation within X. strigosa clade.

TAXONOMY

Laccaria striatula (Peck) Peck. Bull. N.Y. St. Mus. 157: 93 (1912) [1911] (Figs. 1 and 5)

Description: Pileus: Diameter ranging from 15 to 40 mm., convex to flattened, with flesh pink to pinkish brown coloration, striated. Lamellae: Adnate, thick, orange-pinkish. Stipe: Colored in shades of orange, pinkish, or brown, finely fibrillose, 20–50 mm × 2–4 mm. Basidia: Clavate-shaped, 4-spored, with dimensions of 53–68 × 12–14.5 μm. Basidiospores: Globose shape, echinulate with spines, measuring 8.012.0 × 9.0–11.5 μm; Q = 0.9–1.3; n = 20. Cheilocystidia rarely observed, filamentous, flexuous. Pileipellis a cutis, hyphae interwoven, cylindrical, bifurcating, clamped. Pileocystidia not observed.

Habitat: Found on the ground of the forests.

Specimen examined: Location: Gangwon-do, Wonju-si, Korea. Coordinates: 37°21ʹ47.75ʺN

Specimen examined: Location: Gangwon-do, Wonju-si, Korea. Coordinates: 37°25ʹ12.12ʺN 128°3ʹ13.53ʺE, alt. 322 m. Collection date: Sep. 14, 2022. Specimen voucher: CKU20220914-14.

Remarks. The description based on the Korean collection is in accordance with the holotype description [28]. Xerula strigosa has been documented in both China and Pakistan as well. Hence, considering its morphological features and molecular analysis, this represents the species’ third recorded occurrence.