Cystodermella cinnabarina (Albertini & Schweinitz: Fries) Harmaja (2002:45). (Figs. 3C–D)

Holotype:—none preserved or designated. Neither specimen nor illustration present in Schweinitz's herbarium (now in PH).

Neotype (designated here):— ESTONIA. Saaremaa: Harilaid, in Pinus sylvestris forest on sand dunes, on moss, 58.46372°N, 21.91358°E, 20 September 2007, V. Liiv (TUF106009; ITS sequence: GenBank/ UNITE: PP575898 / UDB011139).

Basionym: Agaricus granulosus Batsch var. cinnabarinus Albertini & Schweinitz (1805:147) .

Synonyms: Agaricus cinnabarinus (Albertini & Schweinitz) Fries (1857:29) .

Cystoderma cinnabarinum (Albertini & Schweinitz: Fries) Fayod (1889:351).

Agaricus terryi Berkeley & Broome [as Terreii] (1870:462).

Cystoderma terreyi (Berkeley & Broome) Harmaja (1978:30) .

Cystoderma texense Thiers [as texensis] (1957:721).

Cystoderma myriadocystis Heinemann & Thoen (1973:14) .

Cystodermella lactea Musumeci (2006:25) .

Cystodermella mazahuensis Pérez Moreno, Moreno-Solís & Ayala-Vásquez (Ayala Vásquez et al. 2023:4) .

Specimens studied:— USA. Texas: Montgomery Co., Sam Houston National Forest near Richards, in Pinus and Quercus woods, gregarious in humus, 3 December 1951, H.D. Thiers 1419 (holotype of Cystoderma texense, MICH 10541!). UNITED KINGDOM. Scotland: Morayshire, Forres, 29 October 1870, M. Terry (holotype of Agaricus terryi, K(M)140617!).

Notes:— Cystodermella cinnabarina is characterised by a pileus in shades of orange to reddish, rarely in shades of brown or white (it is common that the basidiomata fade; compare Figs. 3C–D), ellipsoid to oblong basidiospores, 3.0–5.0 × 2.0–3.5 µm (av. 4.0 × 2.6 µm), Qav = 1.5–1.6 (av. 1.5), and with narrowly lageniform caulo-, cheilo- and pleurocystidia, 26–50 × 4–10 × 2–4µm, with a spear-like apex covered with crystals.

Saar (2016) showed conspecificity of taxa having a brown pileus and stipe ( C. myriadocystis, ITS: LN878145) or white basidiomata ( C. lactea, ITS: LN878144) to C. cinnabarina based on ITS sequences from the type specimens. In our analyses, ITS sequences from the holotypes of Cystoderma texense, Cystodermella mazahuensis, and C. terryi clustered together with Cystodermella cinnabarina (Fig. 1). Of the four names clustered in this clade, Cystodermella cinnabarina is the oldest, making the others synonyms.