Contribution to morphology and ecology of Polyporus rhizophilus

The distribution and ecological conditions of the occurrence of Polyporus rhizophilus 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 Stipa capillata in the skorocice reserve near Busko zdrój and at an anthropogenic site among Dactylis glomerata, Poa annua and P. trivialis 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 kieleckosandomierska upland. This locality is isolated ecologically from the two remaining Polish localities situated in the xerothermic grasslands.


MaTeriaL anD MeThoDs
The results are part of long-term mycocoenological research conducted by authors in the Wyżyna Małopolska upland between 1986 and 2008 and are supplemented by literature data (sałata 1977;Wojewoda 2003).Biocoenotic and habitat conditions of the occurrence of Polyporus rhizophilus were characterised using phytosociological relevés and habitat descriptions.Phytosociological relevés were conducted with the commonly used Braun-Blanquet method.The nomenclature of vascular plants follows Mirek et al. (2002).
Microscopic characters of the fruit-bodies, such as spores, basidia and hyphae, were measured using a micrometric scale.The drawings of such elements were based on photographs taken with a light microscope.
herbarium specimens were deposited in the Fungarium of the Department of nature and Mathematics, Jan kochanowski university of humanities and sciences, kielce.
localities in poland.Prior to this paper, Polyporus rhizophilus was known only from one locality in Dwikozy in the Wyżyna sandomierska upland (geographic coordinates: 50°44'n and 21°47'e; aTPoL square ef 82), where it produced fruitbodies on the roots of Stipa capillata in the Sisymbrio-Stipetum capillatae association (sałata 1977;Wojewoda 2003).Two new localities were found in the Wyżyna Małopolska upland: one in the town of końskie and one in the skorocice reserve near Busko zdrój (Fig. 2).
The locality in końskie is situated in the ne part of an urban park (geographic co-ordinates: 51 o 12' n and 20 o 25' e; aTPoL square -ee 32). a phytosociological relevé was performed to examine the plot in which Polyporus rhizophilus occurred (400 m 2 ).The tree layer sparse, crown density up to 50%, the shrub layer absent, the cover of the herb layer 85%, the moss layer scarce.Grass in the herb layer mown regularly; participation of few perennials.Grass-mowing considerably hindered the identification of the trophic relationship between the fungus and the grass species.geographic distribution.Polyporus rhizophilus is known mostly from scattered localities in central, southern and eastern europe as well as from northern africa and asia (rauschert 1962; kotlaba 1984).it was recently recorded in south america (silveira, Wright 2005;Gomes-silva, Gibertoni 2009).Polyporus cryptopus, a species with a very similar morphology, biology and ecological requirements, occurs on prairie grasses of the Great Plains in north america.however, relationships of phylogenetic affinity between Polyporus rhizophilus and P. cryptopus are not clear and it is unknown if both are the same species or two different ones (Gilbertson, ryvarden 1987;ryvarden, Gilbertson 1994).The distribution of P. rhizophilus in europe and the history of recent records are given by kreisel (2006).it is a rare component of the mycobiota everywhere.Polyporus rhizophilus is limited to continental and sub-Mediterranean thermophilous steppe grasslands and extrazonal xerothermic communities within its range (ryvarden, Gilbertson 1994;Leshan 2008).it occurs on roots of numerous grass species belonging to genera such as Bothriochloa, Calamagrostis, Chrysopogon, Cynodon, Digitaria, Elymus, Festuca, Poa and Stipa (Jülich 1984;ryvarden, Gilbertson 1994).however, it has mostly been recorded on Stipa and is usually thought to be connected with this genus.

Discussion
Polyporus rhizophilus usually occurs in steppe and xerothermic grasslands that develop in the continental climate.it is therefore interesting that the fungus was recorded in an urban park in the town of końskie outside the northern range limit of the species where conditions are different from its ecological requirements.The occurrence of P. rhizophilus at an anthropogenic locality in which grasses connected with xerothermic habitats are absent may suggest that other factors enabling the development of the fungus are responsible for it.Global warming and climate continentalisation in some regions seem to play a role.The influence of climatic changes on the range extension of some fungal species in discussed by kreisel (2006).according to kreisel (l.c.), the geographic range of the species has considerably expanded northwards in the last few years, which may be related to global warming.Polyporus rhizophilus remains either a rare or very rare component of the mycobiota worldwide despite this tendency.
While conditions favourable for range broadening have been observed, serious threats to the species are also recorded.They result from adverse biocoenotic changes that have been taking place in xerothermic grasslands and transformations of the usage type.overgrowing and excessive burning of grassy xerothermic communities cause the displacement and disappearance of grasses on which Polyporus rhizophilus grows and, consequently, the disappearance of its localities.Threats to and protection of Polyporus rhizophilus in Poland are related to the development dynamics, existence and protection of xerothermic biocoenoses.Polyporus rhizophilus is a very rare component of the mycobiota in Poland and its natural localities must be actively protected in situ. it is included in the red list of fungi threatened in Poland as endangered species (e) (Wojewoda, Ławrynowicz 2006).