Crinipellis xiaoxinganlingensis

Crinipellis xiaoxinganlingensis nom. prov. Figs 14 G – I, 18 Etymology. “ xiaoxinganlingensis ” refers to the type locality, Xiaoxinganling, the Lesser Khingan Range in Northeast China. Description. Basidiomata small. Pileus 0.3–0.6 cm diam., convex to plane, slightly depressed at center; surface cream-yellow (RAL 1034), covered with reddish-brown (RAL 3011) to clay-brown (RAL 8011), radially arranged tomentose scales; scales denser at center, dark copper-brown (RAL 8004), becoming sparse toward margin. Context cream (RAL 9001), thin; odor indistinct. Lamellae free, moderately dense, unequal, L = 20–26, I = 1–3, cream (RAL 9001), bruising reddish-brown (RAL 3011), but showing no immediate or only very faint color change when cut with a sharp knife; color unchanged when dry. Stipe 1.2–1.9 cm long, 1–3 mm thick, cylindrical, equal or slightly thicker at base, hollow, fibrous; surface clay-brown (RAL 8001), rough, densely covered with reddish-brown (RAL 3011) tomentose scales; base directly attached to substrate, with black rhizomorphs, but not arising from the rhizomorphs. Basidiospores (6.2) 6.7–9.8 (9.9) × (3.7) 3.8–5.5 (5.6) µm, Q = (1.24) 1.36–2.1 (2.11) [1.72 ± 0.24], oblong-ellipsoid, smooth, thin-walled, hyaline, containing oil droplets, inamyloid. Basidia 23–29 × 6–9 µm, clavate, thin-walled, hyaline, inamyloid, 4 - (rarely 2 -) sterigmate. Basidioles 16–28 × 4.4–7.5 µm, clavate to cylindrical, hyaline, smooth, thin-walled, inamyloid. Cheilocystidia 19–26 × 6–9 µm, clavate, thick-walled, hyaline; apex bearing 2–4 digitate branches, branches 4–8 µm long. Pleurocystidia not observed. Lamellar trama subregular; hyphae 3–5 µm wide, thin-walled, hyaline, inamyloid. Pileus hairs 125–327 × 3–6 µm, setose, thick-walled, pale brown, dextrinoid. Pileus trama a cutis, inamyloid, brown in water, unchanged in 5 % KOH. Stipe hairs 98–361 × 4–6 µm, setose, thick-walled. Stipe trama composed of cylindrical cells 3–5 µm wide, yellowish-brown with a faint greenish tint in 5 % KOH. Clamp connections present. Materials examined. CHINA • Heilongjiang Province, Yichun City, Fenglin County, Wuying National Forest Park, scattered on dead twigs of shrubs, 26 July 2023, 48°14'10"N, 129°12'39"E, alt. 392 m, W. N. Hou & L. Y. Zhu, FJAU 69447 (H 2307344). • Heilongjiang Province, Yichun City, Fenglin County, Wuying National Forest Park, scattered on dead twigs of shrubs, 26 July 2023, 48°14'07"N, 129°12'51"E, alt. 390 m, W. N. Hou & L. Y. Zhu, FJAU 69448 (H 23073442). Notes. The morphological characters of Cr. xiaoxinganlingensis nom. prov. conform to the generic concept of Crinipellis established by Patouillard (Patouillard 1889; Kerekes and Desjardin 2009). Its diagnostic features, including a cream-yellow pileus covered with reddish-brown, radially arranged tomentose scales, clavate cheilocystidia, inamyloid lamellar trama, and a yellowish-brown stipitipellis with a faint greenish tint in 5 % KOH, also match the supplementary characters proposed for Crinipellis by Kerekes and Desjardin (2009). On morphological grounds, the assignment of this species to Crinipellis is therefore reasonable. Phylogenetic evidence, however, complicates its generic placement. Although the two specimens form a well-supported clade outside the main Crinipellis clade, their morphological characters are consistent with those of Crinipellis, leaving their generic placement uncertain. During field observations, Cr. xiaoxinganlingensis nom. prov. exhibited a distinct color change in the lamellae upon bruising. Despite this prominent diagnostic character and its unusual phylogenetic position (Fig. 1), the species is not formally described as new at this stage. This decision is based primarily on two considerations. First, only two collections originating from the same geographic locality have been examined to date, which is insufficient for evaluating the full range of morphological variation within the taxon. Second, the generic placement of Cr. xiaoxinganlingensis nom. prov. remains unresolved. Prematurely publishing it as a new species of Crinipellis could further complicate genus circumscription and render the current generic circumscription non-monophyletic. Phylogenetic analyses also indicate that the clade containing this taxon may constitute an independent genus-level clade. Even so, erecting a new genus is not appropriate at present for several reasons. A clear suite of shared generic characters cannot yet be defined for this lineage. Beyond the bruising reaction and its unique habitat, no additional key morphological characters have been identified that clearly separate it from closely related genera. These two features alone are insufficient to justify the recognition of a new genus. It also remains uncertain whether the discovery of this taxon points toward a broader systematic range for Crinipellis. Accordingly, a detailed description, illustrations of diagnostic characters, and sequence data are provided herein for Crinipellis xiaoxinganlingensis nom. prov. These data aim to support future collections and comparative studies of taxa occupying similar phylogenetic positions and may help achieve a more robust resolution of this taxonomic problem. Cr. xiaoxinganlingensis nom. prov. is currently known only from the Lesser Khingan Mountains in Northeast China. The Lesser Khingan region lies within the mid-temperate continental monsoon climate zone and features mixed coniferous-broad-leaved forests (e. g., well-preserved primary Pinus koraiensis Siebold & Zucc. forests) (Sun et al. 2026). A distinctive forest-floor microenvironment may be formed by the cold climate, seasonally frozen ground, dense canopy, and slowly decomposing litter layer (Zhang and Jia 2023).