Sinohygrocybe tomentosipes

Sinohygrocybe tomentosipes C.Q. Wang, Ming Zhang & T.H. Li, in Wang et al., MycoKeys 38: 67 (2018)

Etymology: The species epithet tomentosipes refers to the tomentose stipe.

Diagnosis: Differs from the other members of the tribe Chromosereae by its larger and more robust basidiomata, concolorous yellow pileus, lamellae and the subsurface of stipe, usually furcate and interveined lamellae and lamellulae, white fibrillose stipe surface, long basidia (up to 80 μm), ratio of basidia to basidiospore length over 5 and even up to 8.

Basidiomata small to medium-sized. Pileus 2.5–6 cm diam., convex to applanate, usually slightly depressed in the centre, smooth, dry but subviscid when wet, light yellow to vivid yellow (3A5–8) or to deep yellow (4A5–8), or light orange to dark orange (5A5–8), becoming paler when dry; margin even, straight or upturned and occasionally split when mature. Lamellae up to 7 mm wide, adnate to sinuate or decurrent, distant, 17–22 lamellae per pileus, with 1–3 lamellulae between two complete lamellae, usually furcate, often interveined or anastomosing at lamella base, thick, concolorous with the pileus; lamellar base and lamellulae irregular and occasionally the whole hymenophore irregular; lamellar edge even and concolorous. Context concolorous with lamellae and pileus, unchanged when cut. Stipe 4–6.5 × 0.6–1.2 cm, central or occasionally eccentric, subcylindrical, moderately to densely covered with white tiny adpressed fibres. Odour indistinct.

Basidiospores 8–10(–10.5) × (4.5–)5–7(–7.5) μm, Q = (1.3–)1.5–1.8, Qm = 1.6– 1.7, ellipsoid to ellipsoid-oblong, ovoid, not constricted, thin-walled, hyaline, smooth. Basidia 41–80 × 4–10 μm, strongly elongated, narrow clavate, 4-spored, thin-walled; sterigmata up to 10 μm long; ratio of basidia to basidiospore length over 5 and up to 8. Hymenophoral trama subregular, yellow, made up of thin-walled hyphae 3–15 µm wide and usually less than 100 μm long and some conducting elements. Pileipellis a cutis, made up of repent hyphae 3–9 µm wide with the terminal elements 30–80 µm long. Stipitipellis a cutis, with thin-walled hyphae (5–7 μm wide). Clamp-connections present in all tissues.

Habitat and known distribution:  Gregarious, caespitose, or scattered in broadleaf forest in subtropical temperate transition zone, so far known only from Sichuan and Hunan Provinces in China.

Index Fungorum number: IF824824

Figure 1. Phylogenetic overview of the family Hygrophoraceae inferred from ITS-LSU-RPB2 data using Maximum Likelihood (ML) method. Typhula phacorrhiza was selected as outgroup. Bootstrap values (≥50%) were presented around the branches. The newly generated sequences are shown in bold.