The genus XEROCOMUS in the Netherlands

The genus Xerocomus is a difficult genus. There are still great problems with regards to species concepts and the interpretation of variability of macroscopic characters. I am currently revising this group for vol. 7 of the Flora agaricina neerlandica, which will be published sometime in 2004.
One of the most typical species we have in our Dutch flora is a species recently described by two students, viz. X. bubalinus. . Thus far it was only known from the Netherlands, but in Oct. 2001 I was lucky to find this species in Autria, along the borders of the Neusiedler See, on sandy soil under Populus. A description of this species is given below:

Xerocomus bubalinus (Oolbekking & van Duin) Redeuilh macroscopical description: Pileus up to 50 mm broad, hemispherical to convex, very delicately ochre-red to red-brown when young, then red-brown (Mu. 7.5YR 3-4/2-4; 5R 4/4-5,5/6, 10YR 4/4-5/6), very irregular rugulose, entirely covered with a fine bloom only later craqing. Tubes adnate, yellow, strongly contrasting with pileus colour (2.5 Y 7-6/6-8), pores remarkably yellow (2.5 Y 8-7/6). Stipe yellow as pores, with vague reddish tinges, especially when young at apex, rather strongly fibrous-grooved lengthwise. Context yellow in pileus and stipe (5 Y 8/6/8), faintly turning blue when cut, particularly in upper part of stipe and lower part of pileus just above the tubes, andalso a pink in the rest of the pileus; context in stipe base orange (5-7.5 YR 7/8)
X. bubalinus Noordel. 1582	X. bulbalinus Noordel. 1584	X. bubalinus Noordel. 1592

Xerocomus bubalinus clearly belongs to the group of X. communis, from which it differs in a few characters: the delicate ochre-brown tinges in the cap (hence the name "bulbalinus"which refers to the colour of a cow), the pink and blue discoloring of the flesh, the lack of true red dots in the stipe base, and also by the shorter spores.