Xerocomellus pruinatus

Description

Xerocomellus pruinatus, formerly known as Boletus pruinatus or Xerocomus pruinatus, is a mushroom in the family Boletaceae native to Europe. The cap color ranges from light brown to dark chestnut brown but maybe a grayish brown, olivaceous brown, reddish-brown, or in some instances such a dark grey that it appears black. It is usually slightly convex and covered in a fine bloom that may remain when fully expanded.

Fruitbody medium to small-sized, boletoid, without veil and ring. Stipe solid, often tapering towards the base. Flesh variously colored, changing or not when exposed to air. Tubes are not separable from each other, instead of tearing apart. Pores are usually angular.

Widespread in Europe, but the true distribution is somewhat obscured and is yet to be justified as it might have been confused in the past with the other members around Xerocomus chrysenteron.

It is generally considered edible, but it is regarded as a 'poor' mushroom.

It was transferred to the new genus Xerocomellus described by Czech mycologist Josef Šutara in 2008.

Common names: Matte Bolete.

Mushroom Identification

1. Cap

   The cap surface of Xerocomellus pruinatus remains felted throughout its development. The caps of young specimens are mid to dark brown, sometimes with a purplish tint, and they are covered in a hoary bloom that is gradually lost as the cap expands and the fruitbody ages.

   Growing to between 4 and 8cm in diameter, the caps have firm, pale flesh that turns slightly blue when cut.

2. Stem

   The yellow stem of Xerocomellus pruinatus is usually finely patterned with red dots, most noticeably on the central and lower parts of the stem. The stem flesh is bright yellow, blueing slightly towards the stem base.

3. Tubes and Pores

   At first pale yellow, the tubes of Matt Boletes terminate in large angular pores that turn blue-green when bruised. The color change is sudden and most marked in mature specimens, and a deep blue stain is left on the hands.

4. Spores

   Subfusiform (Broadly spindle-shaped), smooth; 11.5–14 x 4.5–5.5µm.

5. Spore Print

   Olivaceous-brown.

6. Odor and Taste

   Not distinctive.

7. Habitat & Ecological Role

   In mixed woodland; particularly common under beech trees. The best place to look for Matt Boletes is under Beech trees (Fagus spp.), particularly in parkland but also in beechwoods on limestone or chalk-rich soil.

Look-Alikes

1. Hortiboletus bubalinus

   Has dull orange flesh in the stipe base, smooth spores, weakly incrusted hyphae of the cap cuticle and grows with lime (Tilia) or poplars (Populus), mostly in urban areas.

2. Xerocomellus cisalpinus

   Have striate spores grows mostly in warm broadleaf woodlands.

3. Xerocomellus chrysenteron

   Has cracking cap cuticle with pinkish flesh seen in the cracks and smooth spores.

History

Until 2008, the scientific name Boletus pruinatus was generally used when referring to the Matt Bolete. The currently-accepted scientific name Xerocomellus pruinatus dates from a 2008 publication by Czech mycologist Josef Å utara, whose studied in detail morphological character os this and other closely-related boletes - since further supported by DNA studies.

Synonyms of Xerocomellus pruinatus include Xerocomus pruinatus var. luteocarnosus (Klofac & Krisai), Xerocomus pruinatus (Fr. & Hök) Quél., and Boletus pruinatus Fr. & Hök.

The generic name Boletus comes ​​from the Greek bolos, meaning 'lump of clay'; the specific epithet pruinatus means 'with a fine bloom', or frosted.

Photo sources:

Photo 1 - Author: Holger Krisp (CC BY 3.0)

Photo 2 - Author: Andreas Kunze (CC BY-SA 3.0)

Photo 3 - Author: Strobilomyces (CC BY-SA 3.0)

Photo 4 - Author: Björn S... (CC BY-SA 2.0)

Photo 5 - Author: Björn S... (CC BY-SA 2.0)