Fungalpedia – Note 106 Clitopaxillus
Clitopaxillus G. Moreno, Vizzini, Consiglio & P. Alvarado
Citation when using this entry: Bera et al., in prep – Fungalpedia, Basidiomycota genera, and terminology. Mycosphere.
Alvarado et al. (2018) revised the systematics of the clitocyboid groups of mushrooms based on 18S, 28S, tef1, and rpb2 sequence data and introduced the genus, Clitopaxillus, while establishing a new classification system for the family Pseudoclitocybaceae. Two species, C. alexandri (Gillet) G. Moreno, Vizzini, Consiglio & P. Alvarado (Basionym: Paxillus alexandri Gillet) and C. fibulatus P.A. Moreau, Dima, Consiglio & Vizzini, were accommodated under Clitopaxillus (Alvarado et al. 2018). The name “Clitopaxillus” is derived from the two genera, Clitocybe (Fr.) Staude and Paxillus Fr. under which the type species, C. alexandri was formerly placed (Alvarado et al. 2018). The genus is saprobic and usually found on leaf litter of trees such as Pinus, Cedrus, and Quercus (Alvarado et al. 2018). Clitopaxillus species usually have large convex to planoconvex basidiomata with a fleshy texture, and smooth pileus (Alvarado et al. 2018). The lamellae have a decurrent attachment to the stipe (Alvarado et al. 2018). The basidiospores of Clitopaxillus are amyloid and ovoid (Alvarado et al. 2018). The basidiomata of C. alexandri consists of a reddish-yellow to greyish-brown pileus with pale yellow stipe and has a characteristic cyanic odour (Alvarado et al. 2018). The hyphae of the pileipellis have a trichocutis arrangement with intracellular pigments and some encrustations (Alvarado et al. 2018). No cystidia have been found and clamp connections are present generally in the hyphae of hymenophore and mycelia (Alvarado et al. 2018). Earlier, C. alexandri was placed under various genera such as Clitocybe, Paxillus, and Lepista (Fr.) W.G. Sm. (Gillet 1873, 1876, Alvarado et al. 2018). Since the original material of C. alexandri could not be traced, no typification has been proposed (Alvarado et al. 2018). However, the descriptions C. alexandri given are from specimens collected from an area in western France near to the type locality (Alvarado et al. 2018). Previously, specimens of C. fibulatus were misidentified as C. alexandri but on close examination, the presence of clamp connections in all the tissues, hymenial cystidia, and its occurrence in alpine habitats separated C. fibulatus as a distinct species (Alvarado et al. 2018). Most species of Clitopaxillus are found in Europe, North Africa, and Northern Hemisphere (Alvarado et al. 2018). An edible mushroom from Shanxi Province in North China, C. dabazi L. Fan & H. Liu has been described (Li et al. 2020). This species differs from C. fibulatus and C. alexandri in having a pileus in earthy brownish tones, a clavate and robust stipe, and a typical agaric odour (Li et al. 2020).
Type species: Clitopaxillus alexandri (Gillet) G. Moreno, Vizzini, Consiglio & P. Alvarado,
Basionym: Paxillus alexandri Gillet
Other accepted speautocies: Clitopaxillus fibulautoatus P.A. Moreau, Dima, Consiglio & Vizzini
Clitopaxillus dabazi L. Fan & H. Liu
Figure 1 – a–d. Clitopaxillus dabazi (BJTC FM085, holotype) a Basidiomata. b Basidiospores. c Basidia. d Cheilocystidia. e Clitopaxillus fibulatus (AMB 18222) clamped hyphae. Scale bars: b–d = 5 μm, e = 10 μm. Redrawn from Li et al. 2020 and Alvarado et al. 2018.
Gillet CC. 1873 – Se´ance du 5 mai. Bull. Soc. Linn Normandie 2e serie 7, 153–183.
Gillet CC. 1876 – Les Hyme´nomyce`tes ou Description de tous les Champignons qui Croissent en France 1, 177–560.
Alvarado P, Moreau PA, Dima B, Vizzini A et al. 2018 – Pseudoclitocybaceae fam. nov. (Agaricales, Tricholomatineae), a new arrangement at family, genus and species level. Fungal Diversity 90, 109–133.
Ishika Bera, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand
(Edited by Kevin D. Hyde)