Boletus rhodoxanthus is a fungus of the genus Boletus

Boletus

Boletus is a genus of mushroom, comprising over 100 species. The genus Boletus was originally broadly defined and described by Elias Magnus Fries in 1821, essentially containing all fungi with pores...

. It is a rare, inedible bolete

Bolete

A bolete is a type of fungal fruiting body characterized by the presence of a pileus that is clearly differentiated from the stipe, with a spongy surface of pores on the underside of the pileus...

 found in warm deciduous forests of southern Europe

Southern Europe

The term Southern Europe, at its most general definition, is used to mean "all countries in the south of Europe". However, the concept, at different times, has had different meanings, providing additional political, linguistic and cultural context to the definition in addition to the typical...

 mainly under oak

Oak

An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

 and beech

Beech

Beech is a genus of ten species of deciduous trees in the family Fagaceae, native to temperate Europe, Asia and North America.-Habit:...

, on chalky soil.

Description

B. rhodoxanthus produces a large, colourful fruit body

Basidiocarp

In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...

. The cap

Pileus (mycology)

The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...

 is convex, coloured mostly whitish-grey, and flushed with pink especially towards the margin. The cap expands with maturity and may exceed 20 cm in diameter. The tubes

Hymenium

The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia or...

 are initially yellow in immature specimens, soon becoming bright red, and stain blue when damaged.

The stem

Stipe (mycology)

thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...

 is bulbous when young, but becomes more slender with maturity. It bears a dense carmine network covering an orange-yellow background. The flesh

Trama (mycology)

In mycology trama is a term for the inner, fleshy portion of a mushroom's basidiocarp, or fruit body. It is distinct from the outer layer of tissue, known as the pileipellis or cuticle, and from the spore-bearing tissue layer known as the hymenium....

 is bright yellow, turning blue when cut but only in the cap and not in the stem base. It has a mild taste.

The spore

Spore

In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

s are olive-brown in colour, ellipsoid to fusiform, sized 10-15 by 4-5.5 μm.

Edibility

B. rhodoxanthus is poisonous and unsuitable for consumption, although its toxicity varies significantly from region to region depending on the substrate.

Similar species

• Boletus legaliae
  Boletus legaliae
  Boletus legaliae, previously known as B. splendidus or B. satanoides, is a basidiomycete fungus of the boletaceae family. It is poisonous, with predominantly gastrointestinal symptoms, and is related to Boletus satanas.-Taxonomy:...
  
   grows with oak, and has a distinctive smell of chicory
  Chicory
  Common chicory, Cichorium intybus, is a somewhat woody, perennial herbaceous plant usually with bright blue flowers, rarely white or pink. Various varieties are cultivated for salad leaves, chicons , or for roots , which are baked, ground, and used as a coffee substitute and additive. It is also...
  
  . Its cap is initially grey and then later flushes carmine from the rim.
• Boletus rhodopurpureus
  Boletus rhodopurpureus
  Boletus rhodopurpureus is an inedible fungus of the genus Boletus, found in coniferous forests mostly near silver fir or spruce on chalk, mainly at higher altitude.- Description :...
  
   grows in mixed woodland, and also bears red-coloured pores and stem. It has a reddish cap with pink or crimson overtones, and flesh that stains deep blue throughout.
• Boletus satanas grows in a similar habitat, and shares many features with B. rhodoxanthus including a whitish cap. However, its cap lacks flushes of pink, its flesh is whitish and turns pale blue all over when the fungus is sectioned.

See also

• List of Boletus species