Leccinum aurantiacum: The Ultimate Mushroom Guide

About The Leccinum aurantiacum Mushroom

Leccinum aurantiacum is an edible bolete of the genus Leccinum. This is a favorite species for eating and can be prepared as other boletes. Its flesh turns very dark when cooked. This large mushroom can be found in late summer and autumn under conifers and deciduous trees. It grows solitary or in small scattered groups on soil specifically under aspen.

The peculiar characteristics of this genus are: the stem, much slender, normally enlarged at the base and covered by more or less thick scales, at the beginning whitish, then blackish when old; the hymenophore formed by very thin and long tubules, rounded or free at the stem, detachable from the flesh of the cap, whitish, yellow or yellowish, grey or whitish-grey with very small pores concolorous to the tubules; the flesh, soft in the cap and fibrous in the stem, of white or yellow color, staining when cut.

It may be mistaken with the Leccinum vulpinum Watling, which, however, grows under conifer and has on the stem, blackish scales since young; the Leccinum quercinum Pilat & Dermek, which however has a more brownish cap, the small scales of the stem are fluffy, initially white, then brownish; the Leccinum versipelle (Fries) Snell, growing under birch, which has however a lighter cap with more yellow hues and the roughness of the stem are dark since the beginning.

Other names: Red-Capped Scraber Stalk, Orange Oak Bolete.

Leccinum aurantiacum Identification

1. Cap

   Initially globose or deeply convex and usually tomentose (finely felty), becoming shallowly convex or flattening completely and often rather misshapen with a finely scaly and less tomentose surface. The cap margin overhangs the pore surface by typically 2 to 4mm, usually in the form of roughly-triangular flaps; various shades of brick red to date brown; 5 to 15cm across when fully expanded.

2. Tubes and pores

   The circular tubes are broadly adnexed or adnate to the stem; they are 1 to 3cm long, creamy-white gradually becoming pale brown, and they terminate in pores that are similarly colored, angular, and less than 0.5mm in diameter. When bruised, the pores turn pinkish grey and eventually dark grey.

3. Stem

   White or buff and 5 to 25cm tall, the stems of Leccinum aurantiacum are 1.5 to 5cm in diameter,. Immature specimens often have barrel-shaped stems; at maturity most stems are more regular in diameter, tapering in slightly towards the cap and sometimes slightly clavate at the base. Reddish-brown woolly scales cover the whole of the stem surface but are noticeably more dense on the lower part of the stem; these stem scales become dark brown as fruitbodies age.

4. Stem flesh

   The cap and stem flesh is white when freshly cut (far left) but darkens and often turns slightly blue towards the base when it is handled, broken or cut (near left).

5. Spore print: Olivaceous buff.

Leccinum aurantiacum Taxonomy & Etymology

The Orange Oak Bolete was described in 1781 by French naturalist Jean Baptiste Francois (Pierre) Bulliard, who gave it the binomial scientific name Boletus aurantiacus. The currently-accepted scientific name Leccinum aurantiacum dates from an 1821 publication by British mycologist Samuel Frederick Gray (1766 - 1828).

Synonyms of Leccinum aurantiacum include Boletus rufus Schaeff., Boletus aurantiacus Bull., Leccinum aurantiacum var. quercinum Pilát, Leccinum quercinum (Pilát) E. E. Green & Watling, and Leccinum populinum M. Korhonen.

Leccinum, the generic name, comes from an old Italian word meaning fungus. The specific epithet aurantiacum means orange - a reference to the cap color.