Fungalpedia – Note 204, Xerocomus


Xerocomus Quél. 

Citation if using this entry: Bera et al. 2024 (in prep) – Fungalpedia, Basidiomycota 1. 

Index FungorumMycoBank, Facesoffungi, GenBank, Fig. 1

Classification: Boletaceae, Boletales, Agaricomycetes, Basidiomycota, Fungi.

Xerocomus was first introduced by Quélet (1887) and typified by X. subtomentosus (L.) Quél. (Quélet 1888). The systematic classification of Basidiomycetes has traditionally relied on the morphology of basidiomata, and Xerocomus has adhered to this convention for many years. The generalized application of the name “Xerocomus” to a diversity of taxa has reflected its heterogeneity and has led to many synonyms (Singer 1986Ladurner & Simonini 2003Zhang et al. 2013). Some mycologists have often merged Xerocomus into Boletus L., while others regard it as a distinct genus (Watling & Hills 2005, Hills 2008, Zhang et al. 2013). It was suggested that based on the characteristics of the hymenophoral trama, the European species of Boletus can be distinguished from Xerocomus. However, non-European ones will still be ambiguous (Singer 1945Oolbekkink 1991Lee et al. 2023). 

Phylogenetic studies have inferred the non-monophyletic nature of Xerocomus (Binder & Hibbert 2006). It has always been challenging to distinguish the species in Xerocomus (Peintner et al. 2003). For most of them, the typical ornamentation of the basidiospores, hymenophoral trama of phylloporoid and non-gelatinous nature, non-glutinous trichoderm type of pileipellis and non-gelatinous, loosely arranged, divergent lateral stratum in the peripheral layers of the stipe, are characteristic features of Xerocomus species (Šutara 2008).  The study of basidiospore morphology has become an important morphological character to delimit the taxa in this genus (Lee et al. 2023). 

The multi-gene (LSU, tef1-α, rpb1, and rpb2) phylogenetic analyses of Xerocomus revealed six lineages: Xerocomus s.str., Hemileccinum Šutara, Xerocomellus  Šutara, and three other unnamed clades (Wu et al. 2014). Bacillate spore ornamentation is the defining characteristic of Xerocomus s.str. (Šutara 2008). The overall slender and less fleshy appearance of the basidiomata, pileus surface never viscid or glutinous when wet, and angular pores at maturity of ca 1–3 mm adnate tubes of 15 mm long are some of the identifying characters of the members of Xerocomus s.str. (Šutara 2008). This ectomycorrhizal boletoid genus currently encompasses around 115 species, according to the documentation under Species Fungorum (2023). 

Synonyms: Versipellis Quél.,

Type species: Xerocomus subtomentosus (L.) Quél.  

Other accepted species: (Species Fungorum – search Xerocomus

Figure 1 – Xerocomus longistipitatus (holotype, DC 16-056). a Fresh basidiomata. b Pore surface. c Basidiospores. d Basidia. e Caulocystidia. f Pileipellis. g Cheilocystidia. h Pleurocystidia. Scale bars: c–e, g & h = 10 μm, f = 25 μm. Taken from Chakraborty et al. (2017).



Binder M, Hibbett DS. 2006 – Molecular systematics and biological diversification of Boletales. Mycologia, 98(6), 971–981.

Chakraborty D, Parihar A, Nikita Mehta, Baghela A, Das K. 2017 – A new species of Xerocomus (Boletaceae) from India. Mycosphere, 8(1), 44–50. 

Hills AE. 2008 – The genus Xerocomus: A personal view, with a key to the British species. Field mycology, 9(3), 77–96

Ladurner H, Simonini G. 2003 – Xerocomus s. l. Fungi Europaei, vol. 8. Edizioni Candusso, Alassio. 

Lee SML, Helfer S, Watling R. 2023 – Defining Xerocomus s. str. (Boletaceae) in Malesia. Journal of Tropical Biology & Conservation (JTBC), 20, 27–43. 

Oolbekkink GT. 1991 – The taxonomic value of the ornamentation of spores in ‘the Xerocomus-group’of Boletus. Persoonia-Molecular Phylogeny and Evolution of Fungi, 14(3), 245–273

Peintner U, Ladurner H, Simonini G. 2003 – Xerocomus cisalpinus sp. nov., and the delimitation of species in the X. chrysenteron complex based on morphology and rDNA-LSU sequences. Mycological Research, 107(6), 659–679

Quélet L. 1887 – Xerocomus. In: Mougeot, A., Ferry, R. & Roumeguère, G. (eds.) La flore des Vosges, Champignons, Algues: In: Louis, L. Le Département des Vosges, Description – Histoire – Statistique. Tome II. La flore des Vosges. Épinal: E. Busy. 477–478.

Quélet L. 1888 – Flore mycologique de la France. Paris, France

Singer R. 1945 – New Bolataceae from Florida (a preliminary communication). Mycologia, 37(6), 797–799. 

Singer R. 1986 – The Agaricales in modern taxonomy, 4th edition. Koeltz Scientific Books, Koenigstein, Germany. 

Šutara J. 2008 – Xerocomus sl in the light of the present state of knowledge. Czech Mycology, 60(1), 29–62. 

Watling R, Hills AE. 2005 – Boletes and their allies. Boletaceae: Strobilomycetaceae: Gyroporaceae: Paxillaceae: Coniophoraceae: Gomphidiaceae (revised and enlarged edition). British Fungus Flora. Agarics and Boleti, 1, 173

Wu G, Feng B, Xu J, Zhu XT, et al. 2014 – Molecular phylogenetic analyses redefine seven major clades and reveal 22 new generic clades in the fungal family Boletaceae. Fungal Diversity, 69, 93–115. 

Zhang M, Li TH, Bau T, Song B. 2013 – A new species of Xerocomus from Southern China. Mycotaxon, 121(1), 23–27. 


Entry by

Ishika Bera, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand


(Edited by Kevin D Hyde, Samaneh Chaharmiri-Dokhaharani, & Achala R. Rathnayaka)