Facts & Profile

Red cracking bolete Xerocomellus chrysenteron, Boletus chrysenteron

Xerocomellus chrysenteron, formerly known as Boletus chrysenteron or Xerocomus chrysenteron, is a small, edible, wild mushroom in the family Boletaceae. These mushrooms have tubes and pores instead of gills beneath their caps. It is commonly known as the red cracking bolete.

Description & appearance

Young specimens of X. chrysenteron often have a dark, dry surface, and tomentose caps which might easily be mistaken for Bay Boletes Imleria badia. When fully expanded, caps are 4 to 10 cm (1.6–4 in) in diameter with very little substance and thin flesh that turns a blue color when slightly cut or bruised. Caps mature to convex and plane in old age. Cracks in the mature cap reveal a thin layer of light red flesh below the skin. The 10 to 15 mm-diameter stems have no ring, are bright yellow and the lower part is covered in coral-red fibrils and has a constant elliptical to fusiform diameter throughout its length of 4 to 8 cm tall. The cream-colored stem flesh turns blue when cut. X. chrysenteron has large, yellow, angular pores, and produces an olive brown spore print.

Fruit bodies of Xerocomellus chrysenteron are also prone to infestation by the bolete eater (Hypomyces chrysospermus).

Macroscopic observation of Xerocomellus chrysenteron is not sufficient to determine this species with certainty, as many intermediate forms occur between it and other taxa; in particular, some forms of B. pruinatus and Hortiboletus rubellus are hardly distinguishable from B. chrysenteron without the aid of microscopic characters. B. porosporus is also similar to this species, but it is easily separated on account of the whitish under layer and truncate (chopped off) spores. Also this species is easily confused with B. declivitatum.

Xerocomellus chrysenteron is considered edible but not desirable due to bland flavor and soft texture. The pores are recommended to be removed immediately after mushrooms are picked as they rapidly decay. Young fungi are palatable and suitable for drying, but they become slimy when cooked; mature specimens are rather tasteless and decay quickly.

Distribution & habitat

Xerocomellus chrysenteron grows singly or in small groups in hardwood/conifer woods from early fall to mid-winter. It is mycorrhizal with hardwood trees, often beech on well drained soils. It is frequent in parts of the northern temperate zones. The species has been recorded in Taiwan. It has been introduced to New Zealand, where it grows in groups under introduced deciduous trees.

This species may not be as common as once thought, having been often mistaken for the recently recognised B.cisalpinus Simonini, Ladurner & Peintner.