<em>Tulostoma</em> genus Pers.: Pers. is represented in Poland by five species (Wojewoda 2003). Only two of those: <em>Tulostoma brumale</em> Pers.: Pers. and <em>T. fimbriatum</em> Fr. can be considered as a relatively common while others such as: <em>Tulostoma kotlabae</em> Pouzar, <em>T. melanocyclum</em> Bres. and <em>T. squamosum</em> (Gmelin in L.): Pers. are very rare. Observations of macrofungi of xerothermic habitats at the Nida Basin (Central Poland), demonstrated the existance of many varieties of particular taxa until now not listed in the Polish mycological literature, and also new sites of all so far described <em>Tulostoma</em> species. Recording of lower taxa such as: <em>Tulostoma brumale</em> Pers. var. <em>longipes</em> (Czern.) J. E. Wright, <em>T. brumale</em> Pers. var. <em>pallidum</em> (Lloyd) J. E. Wright, and <em>T. fimbriatum</em> Fr. var. campestre (Morgan) Moreno are identified at the study area.

A b s t r a c tIn the Chęciny district, xerothermic grasslands developed on deforested slopes of limestone hills, truncated folds, and mounds. Their origin is directly connected with agricultural and pastoral farming of man. Xerothermic grassland belongs to the class Festuco-Brometea, and the alliance Cirsio-Brachypodion. The plant association Thalictro-Salvietum pratensis is the most widespread in this area. The xerothermic grasslands have their own characteristic biota of macromycetes. The following steppe, xerothermic, and thermophilous fungi deserve special attention: Agaricus bernardii, Camarophyllus virgineus, Conocybe sienophylla, Entoloma incanum, Hygrocybe konradii, H. persistens, H. reae, Lepiota alba, and Leucopaxillus lepistoides.As a result of the xerothermic swards being progressively overgrown by shrubs and trees, among others, by Pinus sylvestris, one can find fungi species accompanying this tree: Suillus collinitus, also fungi producing underground fruit bodices Rhizopogon obtextus and Rh. roseolus. The main factors threatening xerothermic grasslands of the Chęciny district are, among others, the devastation and disappearance of natural habitats, often as a result of inappropriate human land management as well as the pollution of air, water, and soil. The effective protection of rare, threatened, and also legally protected fungi species is only possible by protecting their natural habitats as a whole.

A b s t r a c tXerothermic habitats of protected sites in the Nida Basin are of special natural value. The richness of steppe plant species contributes to the biodiversity of grassland ecosystems and increases the floristic and landscape uniqueness of Ponidzie. A rich thermophilous biota of interesting steppe macromycetes (Basidiomycetes) develops in the xerothermic vegetation in the area.As preliminary investigations into macrofungi in xerothermic communities in the Nida Basin have shown, many very rare and valuable species as well as species new to the Polish mycobiota occur in the study area. Several rare species of gasteroid fungi, such as Geastrum minimum and G. schmidelii, were found in patches of Sisymbrio-Stipetum capillatae. Many taxa are indicator species of these biocoenoses. Noteworthy are parasitic macrofungi infecting roots of the genus Stipa: Gastrosporium simplex and Polyporus rhizophilus. Localities of species of the genus Tulostoma: T. brumale, T. kotlabae and T. melanocyclum, T. squamosum, new to the Nida Basin, were recorded in patches of Koelerio-Festucetum rupicolae and Festucetum pallentis. The above fungi are very rare in Poland's mycobiota. They are strongly threatened and are classified as endangered (E). Geastrum minimum and the species of the genus Tulostoma are strictly protected.

The distribution and ecological conditions of the occurrence of <em>Polyporus rhizophilus</em> in Poland are discussed. The species was previously known from only one locality in Dwikozy near Sandomierz. Further localities were found on the roots of <em>Stipa capillata</em> in the Skorocice reserve near Busko Zdrój and at an anthropogenic site among <em>Dactylis glomerata, Poa annua</em> and <em>P. trivialis</em> grasses in an urban park in Końskie. The latter locality is noteworthy as it is situated outside the occurrence range of xerothermic grasslands in the Wyżyna Kielecko-Sandomierska upland. This locality is isolated ecologically from the two remaining Polish localities situated in the xerothermic grasslands.

The authors mention new localities of three, rare species of <i>Gasteromycetes</i> in Poland, connected with xerothermic vegetation.