Habitat and Ecology
Butyriboletus regius occurs in deciduous forests, and it forms ectomycorrhiza principally with Quercus, and it is less frequently reported from Fagus and Castanea forests in our country. Suitable environment is old, sunny, semi-open forests, on wet slopes, with preference for calcareous soils. The species usually produces sporocarps from mid-spring to mid-autumn, infrequently and in a small number while in rainy summers it is documented as more common, producing a higher number of sporocarps.
It has been recorded at 70 sites in the country, broadly dispersed in 30 biogeographic regions (Melovski et al. 2013), at elevation ranges between 400 and 1,600 m. Only one of the known sites is located in a national park, in Galicica NP, in the zone for sustainable use. The species is edible, conspicuous, so it has been searched for in the past, and it has been reported. Nonetheless, since it grows in broadleaf forests, which are the dominant forest cover in the country, an estimation of probable sites has been made (Dahlberg and Mueller 2011). The total number of sites is guesstimated to be twice as high as the current number, thus it is ca. 140 sites.