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
Xerocomus rubellus
Has characteristic orange-red dots in the flesh of the stipe base and does not truncate smooth spores.
Xerocomus ripariellus
Has striate, non-truncate spores.
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Has truncated striate spores but grows in a slightly different habitat, associated presumably with oaks (Quercus).
Xerocomus ripariellus
Has striate, but not truncate spores.
Xerocomus cisalpinus
Has striate, but not truncate spores and grows in warm habitats, associated with oaks (Quercus), beech (Fagus), pines (Pinus) or cedar (Cedrus).
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
Xerocomus fennicus (Harmaja) H. Ladurner & Simonini 2003
Boletus fennicus (Harmaja) Šutara 2007
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)