Suillus subg. Larigni (Singer ex Estadès and Lannoy) R. Zhang, X. F. Shi, G. M. Mueller & P. G. Liu 2025

Shi, Xiaofei, Zhang, Shiru, Mueller, Gregory M., Liu, Peigui, Yu, Fuqiang & Senanayake, Indunil C., 2025, A subgeneric revision of the genus Suillus (Suillaceae, Boletales) and novel taxa from Eastern Asia based on morphology and multigene phylogenies, IMA Fungus 16, pp. e 144260-e 144260 : e144260-

Suillus subg. Larigni (Singer ex Estadès and Lannoy) R. Zhang, X. F. Shi, G. M. Mueller & P. G. Liu comb. & stat. nov.

Basionym.

Suillus sect. Larigni Singer ex Estadès and Lannoy Docums Mycol. 31 (no. 121): 57 (2001).

Etymology.

was derived from “ Larignus ”, meaning of the larch.

Typification.

Suillus grevillei (Klotzsch) Singer , Farlowia 2 (2): 259 (1945).

Diagnosis.

Main features of this subgenus include glabrous and glutinous or dry pileus with scales, solid, annulate stipe, lacking glandular dots, olive brown or dull cinnamon spore print and lacking clamp connections.

Morphology.

Basidiomata stipitate-pileate with tubular hymenophore. Pileus develops from hemispherical to convex or applanate, viscid to glutinous and glabrous, or dry with appressed scales, usually yellowish, orange or brown in maturity, sometimes pellicle separable, context yellow, no color change when cut. Hymenophore adnate to subdecurrent, 1 to 2 per mm, angular. Stipe equal to slightly clavate, solid, lacking glandular dots, veil dry and floccose, in some species context changes color to blue or green when exposed. Spore print olive brown to brown when moist, dull cinnamon when dry.

Basidiospores smooth, oblong or suboblong, ochraceous in KOH, usually 7–11 μm. Basidia 4 - spored, clavate, hyaline yellow in KOH. Cystidia abundant, typically fasciculate, hyaline, or containing brown contents and surrounded by brown amorphous materials in KOH. Pileipellis a layer of gelatinous hyphae, with yellowish hyaline content in KOH. Clamp connections absent.

Habitat.

Scattered to gregarious, ectomycorrizal with Larix .

Known species.

Suillus alpinus , S. aurihymenius , S. bresadolae , S. elbensis , the S. grevillei complex, S. grisellus , S. lariciphilus , S. phylolaricinus , S. tridentinus and S. viscidus complex.

Notes.

Excluding subgenera Boletinus and Fuscoboletinus , the rest of the Suillus – Larix species belong to subgenus Larigni . Section Larigni ( Singer 1986) is very close to the current delimitation of subgenus Larigni because representative species were included from all major clades in this section. But the taxonomic description of section Larigni was not comprehensive and the known diversity was not comparable with the current understanding.

Many new species in the subg. Larigni can be recognized and supported by molecular phylogenies. However, taxonomic treatments applying for the new species are deferred pending further study. More focused study is required for resolving the S. grevillei and S. viscidus complexes with minor morphological variations. More comprehensive collections help to confirm host associations and geographic range of some cryptic new species. Though geographic range seems useful in resolving species in the two complexes, one putative new species of S. grevillei distributes intercontinentally across North America and Europe. East Asia is the diversity hotspot for subgenus Larigni . East Asian collections are found in all major clades of subg. Larigni . Efforts towards the sampling of East Asian Larix have resulted in the discovery of many new species in the subgenus ( Shi et al. 2016). For further studies on the subg. Larigni , it is recommended to use LSU, TEFα- 1 and RPB 2 instead of ITS sequences to resolve phylogenetic relationships.