Xerocomellus fennicus

Description

Xerocomellus fennicus is a fungus in the family Boletaceae. It is very similar to Xerocomellus ripariellus but the flesh is yellow throughout the foot and the cap skin tends to crack in a mesh pattern instead of radial. It is characterized by having vinaceous red aging to olivaceous to grey pileus, and truncate basidiospores with longitudinal ornamentation. Under a microscope, you can see that the spores are truncated and striped (cut off and streaked). Widespread in Finland.

The fact that X. fennicus was a separate species was first noticed at the end of the 20th century, in Finland. The first find for Sweden was made in Södermanland and there are scattered reports from Scania in the south to Dalarna in the north. It has also been reported for Denmark, Austria and the Czech Republic and, possibly, Belgium. It forms ectomycorrhiza with birches and larvae.

Xerocomellus fennicus habitat on soil in fallen leaves under Fagus sylvatica, Quercus petraea and Tilia sp. An old beech forest (mixed with scattered other broadleaved trees) on clay-sandy soil on a slope.

Common names: Punatatti (Finland), Rödsopp (Sweden).

Look-Alikes

1. Xerocomus rubellus

   Has characteristic orange-red dots in the flesh of the stipe base and does not truncate smooth spores.

2. Xerocomus ripariellus

   Has striate, non-truncate spores.

3. Xerocomus marekii

   Has truncated striate spores but grows in a slightly different habitat, associated presumably with oaks (Quercus).

4. Xerocomus ripariellus

   Has striate, but not truncate spores.

5. Xerocomus cisalpinus

   Has striate, but not truncate spores and grows in warm habitats, associated with oaks (Quercus), beech (Fagus), pines (Pinus) or cedar (Cedrus).

6. Xerocomus porosporus

   Has differently colored fruitbodies and truncate non-striate spores.

History

The species was described by Harri Harmaja in 1999 as Boletellus fennicus. It was introduced to Xerocomus by Ursula Peintner, Heidi Ladurner and Giampaolo Simonini in 2003 and then to Xerocomellus by Josef Šutara in 2008. Heidi Ladurner and Giampaolo Simonini assume that X. fennicus is the same species as the North American Xerocomellus intermedius.

The species name fennicus means "from Finland" and means that it was first described from there.

Synonyms

1. Xerocomus fennicus (Harmaja) H. Ladurner & Simonini 2003

2. Boletus fennicus (Harmaja) Šutara 2007

3. Boletellus fennicus Harmaja 1999

Photo sources:

Photo 1 - Author: petri_kuhno (CC BY-NC 4.0)

Photo 2 - Author: nibbon (CC BY-NC 4.0)

Photo 3 - Author: tmacinen (CC BY-NC 4.0)