Xerocomus marekii

Description

Xerocomus marekii is a new species with truncate spores from the Xerocomellus chrysenteron group. It is found in northwestern Bohemia (Czech Republic) and it is characterized mainly by its xerocomoid appearance, red-colored, soon coarsely rimose-areolate pileus, and smooth, truncate spores. Habitat in a deciduous forest dominated by oaks, beech, hornbeam, and lime. Its main morphological characters are the bright red, and soon cracked pileus, the red color at the flesh of the stipe, the grayish-brown colors at the base, and the smooth and truncate spores.

Mushroom Identification

1. Cap

   25-50 (-65) mm wide, hemispherical in youth, then arched to pinnate, sometimes even flat, in velvety youth, with a rolled edge, then finely felted, noticeably poppy from the edge, yellow in cracks, otherwise in youth vivid orange-red, then red-orange with burgundy to crimson hue, in age brownish-red, sometimes lighter on the edge.

2. Tubes

   In youth first yellow, then olive-yellow, pores colored similar to tubes, after creasing slightly bluing to green-blue.

3. Stem

   Almost cylindrical or with a slightly widened lower part, felt-flaked, yellowish to a dirty yellow, especially at the apex, below dirty burgundy red, brownish red to dirty brownish.

4. Flesh

   Buttery in youth, soft in old age, yellowish in a cap, yellow on tubes, dirty yellowish-brown in rubbing, often burgundy in the middle, burgundy reddish in the lower part of rubbing. It is very slightly bluish on the cut.

5. Microscopy

   Spores 11-15 (-19) x 5-7 µm, ellipsoidal spindle-shaped, severed at the apex, smooth.

6. Habitat

   In deciduous forests, mycorrhizal probably with oaks (Quercus).

7. Distribution

   So far known only from the Czech Republic and Hungary. It is possibly more widespread but overlooked and it should be looked for.

Look-Alikes

1. Xerocomus rubellus

   Is distinguished by the characteristic bright orange-red spots in the base of the stipe and also by its non-truncate spores.

2. Xerocomus ripariellus

   Is distinguished on the base of its striate non-truncate spores.

3. Xerocomus fennicus

   Has truncate but striate spores.

4. Xerocomus porosporus

   Has truncate, smooth spores, but is distinguished by the differently colored cap and stipe that do not show red tints.

5. Xerocomus dryophilus

   Has non-truncate, smooth spores.

6. Xerocomus silwoodensis

   Has not blueing flesh and non-truncate, smooth spores.

7. Xerocomus cisalpinus

   Has red forms, but it has striate, non-truncate spores

Synonyms

1. Boletus marekii Šutara & Skála (2007)

2. Xerocomus marekii (Šutara & Skála) Klofac (2007)