# Xerocomellus chrysenteron
**Xerocomellus chrysenteron** (Bull.) Šutara, commonly called the red-cracking bolete, is a species of ectomycorrhizal basidiomycete fungus in the family [Boletaceae](https://www.edgepedia.org/boletaceae), best known for its brown cap that cracks with age to expose a thin layer of red flesh beneath the skin.[1](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?command=show&id=1354920&mode=node) • [2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) It is the type species of the genus *Xerocomellus*, erected in 2008 by the Czech mycologist Josef Šutara when the old, broadly defined genus *Xerocomus* was split into several smaller genera.[3](https://czechmycology.org/_cm/CM60104.pdf)
| Key fact | Detail |
|---|---|
| Current name | *Xerocomellus chrysenteron* (Bull.) Šutara, 2008; basionym *Boletus chrysenteron* Bull., 1791; common name red-cracking bolete[1](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?command=show&id=1354920&mode=node) |
| Classification | Fungi; Basidiomycota; Agaricomycetes; Boletales; Boletaceae; Xerocomellus (NCBI Taxonomy ID 1354920)[1](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?command=show&id=1354920&mode=node) |
| Cap | 4–10 cm across, gray-yellow to brownish, velvety when young, crazing with age to reveal a thin layer of red flesh[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) |
| Stem | 10–15 mm in diameter and 4–8 cm tall, bright yellow flushed with coral-red fibrils, no ring[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) |
| Spores | Subfusiform, smooth, 12–16.5 × 4.5–7 µm; spore print olivaceous brown[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) |
| Habitat | Ectomycorrhizal, mainly beneath conifers and occasionally with beech; fruiting mainly August to November[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) |
| Edibility | Considered edible after thorough cooking, but of poor, soggy texture and little culinary interest[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) |
## Taxonomic history
The French botanist-mycologist Jean Baptiste François Bulliard first described this bolete in 1789 under the name *Boletus communis*, changing the specific epithet to *chrysenteron* in 1791.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) Over the following two centuries the species was shuffled among genera, appearing as *Xerocomus chrysenteron* (Bull.) Quél. and as the homotypic synonym *Versipellis chrysenteron* (Bull.) Quél., 1886, among other synonyms such as *Boletus communis* and *Xerocomus communis* (Bull.) Bon.[1](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?command=show&id=1354920&mode=node)
In 2008 Šutara concluded that *Xerocomus* in its wide concept was a heterogeneous mixture of unrelated groups of species, a view supported by molecular studies showing that *Xerocomus* s. l. is not monophyletic. He classified the European species into more distinctly delimited genera, including the new genus *Xerocomellus*, which contains the group of species close to *Boletus chrysenteron*.[3](https://czechmycology.org/_cm/CM60104.pdf) Recent phylogenetic analysis supports the placement of *X. chrysenteron* as the type species of that genus.[4](https://www.marylandbiodiversity.com/species/5058) The specific epithet *chrysenteron* means 'golden inside', a reference to the bright yellow flesh.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php)
## Description
The cap is shallowly convex, gray-yellow or brownish, dry and finely velvety when young, reaching 4 to 10 cm in diameter when fully expanded, with very little substance and thin flesh. As the cap expands and dries, the skin splits into a cracked, mosaic-like surface that exposes a thin layer of light red flesh below; the cracking is a normal aging feature of the species, not a disease.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) • [5](https://fungiatlas.com/xerocomellus-chrysenteron/) The yellow tubes terminate in large, angular pores that are lemon yellow at first and turn a dirty olive yellow with age.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php)
The stem, 10 to 15 mm in diameter and 4 to 8 cm tall, is fairly constant in diameter along its length, bright yellow, and flushed with coral-red fibrils that give it a 'stick of rhubarb' appearance. When cut, the stem flesh is reddish just below the cortex and cream elsewhere.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) The spores are subfusiform and smooth, measuring 12–16.5 × 4.5–7 µm, and the spore print is olivaceous brown.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php)
Bluing behavior is a contested character. First Nature states that the pores of mature specimens slowly turn greenish blue when bruised, while the flesh blues only very slightly when cut.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) Michael Kuo, an American mycologist and author of MushroomExpert.Com, writes that the true European *Xerocomellus chrysenteron* does not bruise blue and is associated primarily with conifers.[6](https://www.mushroomexpert.com/xerocomellus_chrysenteron.html) [The Italian](https://www.edgepedia.org/the-italian) species card from the Gruppo Micologico Cecinese likewise describes the flesh as turning blue in air only very slowly.[7](https://www.gruppomicologicocecinese.it/FungoScheda.php?id=883)
## Ecology and distribution
*Xerocomellus chrysenteron* is ectomycorrhizal, forming symbiotic root associations with trees, and is found mainly beneath conifers, perhaps occasionally also with beech; fruiting bodies appear mainly from August to November.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) In Britain at least it is much less common than *X. cisalpinus* and prefers either conifers or *Fagus* (beech) as its hosts.[8](https://www.fieldmycology.org/index.php/journal/article/download/159/142) First Nature describes it as probably infrequent in Britain, Ireland, and mainland Europe, noting that historic records may be unreliable because of confusion with closely related species.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) It is also reported from parts of North America, though molecular work shows those records mostly concern other species (see below).[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php)
## The X. chrysenteron species complex and misapplied names
The name *Xerocomellus chrysenteron* has long served as a default label for any xerocomoid bolete with a cracked cap, and a complex of species was included under the label 'Red Cracking Bolete'.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) • [9](https://pmc.ncbi.nlm.nih.gov/articles/PMC7453129/) A 2003 study by Simonini and colleagues, published in *Mycological Research*, described *Xerocomus cisalpinus* as a new species and showed that all examined members of the *X. chrysenteron* complex, including *X. chrysenteron*, *X. cisalpinus*, *X. pruinatus*, *X. ripariellus*, *X. dryophilus*, *X. fennicus*, *X. porosporus*, and *X. rubellus*, represent independent lineages.[10](https://www.cambridge.org/core/journals/mycological-research/article/abs/xerocomus-cisalpinus-sp-nov-and-the-delimitation-of-species-in-the-x-chrysenteron-complex-based-on-morphology-and-rdnalsu-sequences/6B1B9DF21827872D3501783B5F3F6937)
The closest look-alike is *Xerocomellus cisalpinus*, which is very similar and hard to separate in the field; it shows stronger blueing on the tubes and a stem base that turns distinctly blue when cut or bruised, and its spores are finely striated lengthwise rather than smooth.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) • [5](https://fungiatlas.com/xerocomellus-chrysenteron/) Other similar species include the matt bolete *X. pruinatus*, whose cracks are bluish-gray rather than reddish-pink, and *Hortiboletus rubellus*, which has a deeper blood-red to brick-red cap and more evident bluing.[11](https://mushroomhunt.app/library/xerocomellus-chrysenteron) In North America, *Xerocomellus truncatus* is virtually identical to the naked eye and is separated only by its truncated (as if chopped off) spores.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) • [6](https://www.mushroomexpert.com/xerocomellus_chrysenteron.html)
Molecular work on western North American *Xerocomellus* found that collections previously labeled *X. chrysenteron* fall primarily into two species: one common in western North America described as *X. diffractus*, and at least one undescribed species from eastern North America. These are not conspecific with the European *X. chrysenteron* but appear more closely related to each other and to the European *X. cisalpinus*; the true *X. chrysenteron* from Europe appears to be more distantly related within the genus.[9](https://pmc.ncbi.nlm.nih.gov/articles/PMC7453129/)
## Uses and cautions
The species is generally considered edible if cooked thoroughly, but its soggy texture means it is not highly regarded as an esculent.[2](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php) Suggested uses include frying with other boletes, adding to soups and stews near the end of cooking, drying, and pickling young specimens.[5](https://fungiatlas.com/xerocomellus-chrysenteron/) Like many related 'mohovik' boletes, it can accumulate heavy metals from polluted soils, so collection along roads or near industrial sites is discouraged.[5](https://fungiatlas.com/xerocomellus-chrysenteron/)
## References
1. [NCBI Taxonomy Browser: Xerocomellus chrysenteron (Taxonomy ID 1354920)](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?command=show&id=1354920&mode=node)
2. [Xerocomellus chrysenteron, Red-cracking Bolete mushroom, First Nature](https://www.first-nature.com/fungi/xerocomellus-chrysenteron.php)
3. [Šutara, J. (2008). Xerocomus s. l. in the light of the present state of knowledge. Czech Mycology 60(1): 29–62](https://czechmycology.org/_cm/CM60104.pdf)
4. [About Red-cracked Bolete, Maryland Biodiversity Project](https://www.marylandbiodiversity.com/species/5058)
5. [Xerocomellus chrysenteron (Red Cracking Bolete), Identification & Photos, Fungi Atlas](https://fungiatlas.com/xerocomellus-chrysenteron/)
6. [Kuo, M. (2024). Xerocomellus "chrysenteron", MushroomExpert.Com](https://www.mushroomexpert.com/xerocomellus_chrysenteron.html)
7. [Gruppo Micologico Cecinese APS, Scheda n° 883: Xerocomellus chrysenteron di pineta costiera](https://www.gruppomicologicocecinese.it/FungoScheda.php?id=883)
8. [British Mycological Society, Field Mycology: identification of Xerocomellus species](https://www.fieldmycology.org/index.php/journal/article/download/159/142)
9. [Frank, J.L. et al. (2020). Xerocomellus (Boletaceae) in western North America. Mycologia / PMC7453129](https://pmc.ncbi.nlm.nih.gov/articles/PMC7453129/)
10. [Simonini, H. Ladurner & Peintner (2003). Xerocomus cisalpinus sp. nov., and the delimitation of species in the X. chrysenteron complex. Mycological Research](https://www.cambridge.org/core/journals/mycological-research/article/abs/xerocomus-cisalpinus-sp-nov-and-the-delimitation-of-species-in-the-x-chrysenteron-complex-based-on-morphology-and-rdnalsu-sequences/6B1B9DF21827872D3501783B5F3F6937)
11. [Red cracking bolete (Xerocomellus chrysenteron), Mushroom Hunt library](https://mushroomhunt.app/library/xerocomellus-chrysenteron)
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*Topic: Encyclopedia › Life and health › Microorganisms and fungi › Fungi and mycology › Basidiomycete taxa › Agaricomycetes › Boletales › Other Boletaceae genera › Xerocomus and xerocomoid segregates*
*Initially written Sep 17, 2026 · Reviewed: Oct 21, 2026 · Edited: Oct 15, 2026; Oct 21, 2026 · Last review: Oct 21, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license