Karstenia 18: 1-19. 1978 The boletes of Finland 1. Genus Boletus P AA VO KALLIO and HELl HEIKKILA KALLIO, P. and HEIKKILA, H. 1978: The boletes of Finland I. Genus Boletus. - Karstenia 18 : 1-19. The Finnish taxa of the genus Boletus are presented. Boletus impolitus Fr. is recorded for the first time from Finland as are also B. edulis Bull. ex Fr. ssp. edulis f. arcticus Vassilk., f. aurantioruber (Dick & Snell) Vassilk . and f. citrinus (Pelt.) Vassilk . The problem of the delimito:tion of B. spadiceus (Fr.) Que!. and B. lanatus Rostk. is discussed. The Finnish distributions are given for all the taxa, mostly on the basis of herbari­ um material. The only species found throughout the country are B. edulis, B. pipera­ tus and B. subtomentosus; most of them are quite southern in their distribution, many occurring only in the oak zone. Their ecology is discussed. Paavo Kallio, Institute of Biology, University of Turku, SF-20500 Turku 50, Finland Heli Heikkila, Kuopio Museum, Department of Natural History, Kauppakatu 23, SF-70100 Kuopio 10, Finland Introduction forest, where the number of agarics is very high (Nannfeldt 1959). North of this zone is the subarctic P .A. Karsten, a mycological pioneer in Finland, birch zone with oroarctic areas on the mountain devoted his thesis (Karsten 1859) to the polypora­ tops, which correspond to the arctic in many ceous fungi in SW Finland, a group which at that respects (Ahti et al. 1968); in fact, the northernmost time included the boletes. Karsten (1876) reported problems of bolete taxonomy and ecology can be less than 20 bolete species from Finland, although studied already in Fennoscandia. This bioclimatic he mentioned 50 species in his book 'Rysslands, Fin­ zonation is reflected in the distribution of boletes in lands och den Skandinaviska halfons hattsvampar' Finland. An idea of the temperature gradient (Karsten 1882). Most of Karsten's observations and existing between the south and north of the country collections were made in Tammela in South Harne, can be obtained from the accumulated temperatures where Karsten taught at Mustiala Agricultural of the growing season, which are 1300 day degrees College. The number of bolete species known from in South Finland and ca. 500 in northernmost Lap­ Finland has grown in this century: Tuomikoski land, or from the corresponding lengths of the (1955b) listed 26 species certainly found in Finland, growing season, which are ca. 200 and 110 days . and a few varieties and subspecies; Kallio (1976) The differences in the moisture conditions are not listed 49. The area from which the herbarium collec­ very great. However, in the SW corner of Finland tions were taken has also become wider. fruit body development is limited by low moisture Finland and Fennoscandia as a whole are of spe­ more often than in other parts of the country. cial interest from the point of view of taxonomical Being mycorrhizal fungi, many of the boletes are and geographical studies on fungi (cf. Hintikka restricted to the distribution area of a certain host 1931, Nannfeldt 1959), and represent a marginal tree species . This partly accounts for the special area for the group of boletes. Many features typical character of the fungal flora of the oak zone. The of the nemoral zone extend from Central Europe to limits of the coniferous forests are also reflected in the northern border of the 'oak zone' in Fennoscan­ the distributions of some fungi, and some special dia, which is one of the most important mycogeo­ larch-mycorrhiza boletes are limited to areas with graphical limits in this part of Europe (Kallio 1963, planted larch (Larix) species. Bresinsky 1969). Another important geographical The geology of Finland is rather uniform from limit is the northern border of coniferous forests. the ecological point of view. Acid Archean bedrock The coniferous zone lying between these two limits predominates. There are only a few limestone areas is the western extension of the transcontinental taiga and small outcrops of other less acid and basic 2 P. Kallio & H. Heikkila rocks, which are usually clearly reflected in the vege­ portant sources were: Singer (1965, 1967), Kallen­ tation. Some such areas are found in the SW archi­ bach (1926-38), Watling (1970), Knudsen (1974) pelago, where remnants of Silurian formations also and Kalamees & Lasting (1974). When these sources occur (Eklund 1934, Hinneri 1972). are cited the year of publication is normally In hnland human influence is strongest in the omitted. southern part of the country; areas where the The data on the distributions in Sweden and Nor- original ecosystems are almost undisturbed are still way are not taken from monographs, but mainly found in Lapland. The degree of human inter­ from special papers published in various periodicals. ference may also be important as a factor deter­ Some herbarium material has been seen by the mining the distribution of boletes. senior author in the Naturhistoriska Riksmuseet (S) In this paper we have tried to collect recent infor­ in Stockholm, and Dr. Gro Gulden has kindly given mation on the Finnish bolete flora. Our own us information about the herbarium specimens of experience is mainly restricted to the SW corner of many species in the Botanical Museum of the Uni­ Finland, the northernmost part of Lapland, around versity of Oslo (0). Vassilkov's papers (1955, 1966) the Kevo Subarctic Research Station, and the area have been useful for the area east of Finland. Also around Kuopio in eastern Finland. The observations the collections in the herbarium of the Komarov Bo­ of living material have been most important, but tanical Institute of the Academy of Sciences, Lenin­ there are some species which we have not found grad, USSR, and discussions with Dr. B.P. Vassil­ ourselves. The collections in H, TUR, KUO and kov yielded much information, particularly concern­ OULU have been taken into consideration, though ing the Kola Peninsula and the areas round Lenin­ not all the specimens are identifiable. grad. The boletes have already been well described in The data concerning the ecology, dependence on several publications, but many of the descriptions of tree species, etc. are based on our personal observa­ species have neglected the regional vanat10n tions and information on the labels of herbarium possibly existing in their morphology and ecology. material. We have also tried to compare these data One of our aims has been to improve the knowledge with the reports in the literature. of the range of variation. Finland is particularly A key to the genera and species of Boletaceae was suitable for a study of the variation shown by bolete given by the senior author in an earlier publication species occurring at the margins of their ranges. We (Kallio 1976). The species are listed in alphabetical have tried to compare our specimens with the order. descriptions in the studies of Kallenbach (1926-38), Singer (1965, 1967), Watling (1970) and others, and have given detailed descriptions only in the cases where the variation range seems to need some ampli­ fication . Short characterizations are, however, given for all the taxa. Descriptions of the distribution of the boletes in Finland are impaired by the fact that the different parts of the country have not been studied equally thoroughly. The areas most intensively investigated lie around centres of scientific activity or the resi­ dences of enthusiastic mycologists. Therefore, most of the information comes from the country around Tammela, Helsinki, Turku, Kuopio, Oulu and the Kevo Subarctic Research Station in Utsjoki. Lately, however, the general public appears to have become more interested in fungi. The authors have presented some maps in the hope that they may prompt field studies of these fungi, encouraging collectors to find new localities for 'rare' species. ~ · In the lists of herbarium specimens the authors' names have been abbreviated to PK and HH. .... The data on the distribution outside Finland are Fig . 1. Typical habitat of many southern boletes. Parai- mainly obtained from the literature. The most im- nen, Lenholm. Photo P. Kallio . Karstenia 18. 1978 3 Boletus albidus Rocques spring, however, Anemone nemorosa, Hepatica (B. radicans Pers. ex Fr.) nobilis, Ranunculus jicaria and other geophytes are Usually in groups. Cap grayish white, often with a typical components. The soil is rich in nutrients and tint of ochre, particularly at the disc; diameter up to the pH value close to 6. Limestone occurs close to 14 em in our material. Surface smooth, somewhat the area, and lime dust spreading from the Parainen tomentose in young specimens and cracked when lime factory may also have some effect (cf. Rauta­ old. Stem 10 em tall and 3-4 em thick (exceptional­ vaara 1950). The habitat is open to the south and ly 6.5 em thick; S. Hietavuo, oral comm.), yellowish apparently very favourable as regards the tempera­ brown or yellow on the lower part without any ture conditions. It is one of the most typical repre­ reddish touch (we have not seen quite young spe­ sentatives of xerothermic meadow habitats in the cimens). Surface clearly reticulate with light yellow SW archipelago of Finland and is known for its net, which is absent from the tomentose basal part. southern flora elements (cf. Hinneri 1972). Chemi­ Pores and tubes lemon yellow, later somewhat cal analyses of fruit bodies collected in this area greenish, easily turning blue when touched. Flesh suggest some correlation between the general requi­ whitish or yellowish in cap, whitish in stem, turning rements for limestone and the Ca content of boletes intense blue, without red colour changes. Taste (Hinneri 1975). usually somewhat bitter and unpleasant (but accord­ In Sweden also, the species 'prefers light and dry ing to Hietavuo not in all specimens!).