Octaviania asterosperma (hypogeous Basidiomycota) Recent data to ecology and distribution

Dubiel G.: Octaviania asterosperma ( hypogeous Basidiomycota). Recent data to ecology and distribution. acta Mycol. 45 (2): 133–144, 2010. Phylogenetic analyses place Octaviania asterosperma in the Boletales, with Leccinum being the closest relative. results of the structural investigation of O. asterosperma ectomycorrhiza with Fagus confirm this systematic position. in Europe the species is an ectomycorrhizal partner of broad-leaved trees, such as Carpinus, Corylus, Fagus, Quercus and Tilia . This paper aims at presenting the new data to the distribution of O. asterosperma in central Europe. The description of the basidiocarps discovered in Poland in the recent years is also given, together with evidence for the parasitic relationship of Sepedonium laevigatum with O. asterosperma. we also present the information concerning all known localities of the species in Poland and its distribution map. Data on the ecology, distribution and status of O. asterosperma in europe, and some structural aspects of basidiocarps and spores, are also summarized.

presence of exuded latex, colour changes of the peridium after exposure to air (no colour changes, greenish or reddish colour change), presence of sterile base, number of spores produced by single basidium (2, 2-4 or mostly 4), colour and form of gleba (diameter of cavities) and (in lesser extend) characteristics of spores (diameter range, number of spines). all those differences, however, could be connected with different stages of basidiocarp development, or different local conditions of their growth, and may be regarded as intraspecific variation (Montecchi, Sarasini 2000). Octaviania olida was not mentioned in the monograph of Montecchi and Sarasini (2000), but this species seems to be separate from O. asterosperma because of the yellowish colour of peridium and ellipsoid rather than round spores with flattened spines (astier 1993). Thus, in most recent literature O. asterosperma is treated in the broad sense (of Montecchi and Sarasini 2000), and we follow this view in the present paper.
Two variants of the species name exist in the literature: Octaviania asterosperma Vittad. and Octavianina asterosperma (Vittad.) o. Kuntze, and these two names were used by different authors. David and Pegler (1995) proposed to conserve the name Octavianina (Vittad) o. kuntze versus Octaviania Vittad., but this was not followed by Gams (1999), who found the former name only the orthographic version, and thus recommended Octaviania as the proper one.
taxonomical position of Octaviania was not certain for a long time. Together with Sclerogaster r. Hesse and Wakefieldia corner & Hawker, the genus was placed in the family Octavianiaceae within Hymenogastrales (Jülich 1984) or cortinariales (Jülich 1981;Pegler et al. 1993;Montecchi, Sarasini 2000). close relationship of Octaviania with Russula Pers. and Lactarius Pers. was also suggested (Singer, Smith 1960;Hawker 1974). Phylogenetic studies, however, have proved very close affinities of Octaviania with boletoid genera, and now the genus is included within the family Boletaceae, with Leccinum Gray being most probably the closest epigeous relative (Binder, Hibbett 2006;orihara et al. 2010). indeed, the features of ectomycorrhizae formed by O. asterosperma and beech (Mleczko, unpublished) confirm this taxonomic position. The ectomycorrhizae closely resemble those formed by other members of Boletaceae. Emanating hyphae and hyphae of plectenchymatous mantle and rhizomorphs are smooth-walled and clampless. rhizomorphs are typical boletoid, with nodia, backwardly growing hyphae and centrally arranged vessel-like hyphae. Middle mantle hyphae form ring-like pattern. additionally, yellowish pigment can be found within hyphal cells. characteristic features of Octaviania asterosperma ectomycorrhizae are swollen, cystidia-like tips of emanating hyphae, similar to those found, e.g., in ectomycorrhizae of some Boletus species.
in the paper we present a description of collected specimens and distribution of Octaviania asterosperma in Poland, and briefly discuss its ecology and status in europe.

MaTEriaL anD METHoDS
Description of the basidiocarps is based on fresh and dry material. The measurements of microscopical features were taken on dry material mounted in water and 3% KoH. The information on the dimensions of spores and other structures is based on 25-30 measurements. The observations were carried out using niKon E80i light microscope equipped with digital camera coupled with LUcia image analysis system.
For observations in scanning electron microscope (SEM) air dried spores were covered with gold and analyzed using Hitachi S-4700 microscope (Department of electron Microscopy, institute of zoology, jagiellonian university, kraków).
The specimens are deposited in the mycological collection of the insti tute of Botany Herbarium of the Jagiellonian University in Kraków (Kra), and in Herbarium of the Łódź University (LoD F).

Description of collecteD specimens
Figs 1-18 Basidiocarps (Figs 1-4) oblong, rarely subglobose when young, mostly flattened, tuberculate to lobed, up to 2.5 cm wide and 3.5 cm long, white rhizomorphs present at base, young and mature but fresh specimens white, turning pinkish, pink-red and vinaceous red in places when touched and exposed to air, then discolouring dirty ochraceous to brownish, dull grey brown and blackish brown, surface smooth, opaque, felty in mature specimens, glabrescent in old basidiocarps, sometimes cracked in mature specimens, gleba soft, wet and "juicy", not bearing latex but in some specimens with watery exudate, whitish, yellowish white when not mature, becoming yellowish ochraceous, brownish and finally fuscous brown and dark brown at maturity, in some specimens with greenish hue in central part of the basidiocarp, marbled with white dissepiments that vary in thickness, gleba chambers in section irregular in shape, rarely round, ellipsoid or elongated, peridium 0.1-0.2 mm thick, white, discolouring pinkish red and vinaceous when cut, sterile bases mostly evident in mature specimens but reduced, sometimes extending to very short columella. Peridium (Figs 9-10, 15) single-layered, not or hardly separable from gleba, composed of elongated, intermixed hyphae, growing paralelly to the basidiocarp surface, 3-12.5 μm in diameter, terminal elements 20-60 μm long and 4-15 μm in diameter (mean 36.4 and 6.0, respectively), mostly tapering at apex, hyphae without encrustations, yellowish to brownish, some with intracellular yellow pigment, with simple septa. Basidia ( Fig. 17a) clavate, with 1-4 sterigmata, without basal clamp, 21-28 × 10-15 μm, mean 12.3 × 24.1 μm, colourless.
Dissepiments 16) made of thin-walled, smooth, elongated hyphae with simple septa, 2-7 μm in diameter, growing in parallel and interwoven, mixed with distinctly swollen hyphal elements, up to 12 μm in diameter, and pigment-filled hyphae, immersed in matrix.
localities. The fruitbodies were found in twenty two localities in Poland (Fig. 19).
Until recently only three localities of this species were known in Poland, two of them were historical (before 1945; wojewoda 2003) and one contemporary (GrEJ 2010). in the present paper we introduce several new localities of this species in Poland, from Polish western carpathians (Gorce Mts, Beskid Sądecki Mts, Beskid niski Mts, Beskid Śląski Mts), and one from central Poland (Małopolska Upland) (Fig. 19). no localities of Octaviania asterosperma in northern Poland have been found so far. Usually several (up to 20) basidiocarps were found in all recent localities in central Poland (Bilcza, Świętokrzyskie region; GrEJ 2010), and in Gorce Mts (present paper). The collections were found either on calcareous and calcareous-dolomite bedrock (Bilcza, Dębowiec nature reserve) or sandstone bedrock with high contents of calcium (Gorce Mts, Beskid Sądecki Mts). in carpathians Octaviania asterosperma was found associated with Fagus L., in beach-fir forest in lower altitudes, whereas in central Poland it was found under Quercus l., Carpinus l., Tilia l. and Corylus l. gasterocarps were always close to the surface of the soil, beneath litter, in case of old and parasitized by Sepedonium specimens frequently partially exposed. These ecological conditions are in accordance with data from other regions in Europe (e.g., Pilát 1958;Szemere 1965;Pegler et al. 1993;Gminder et al. 2000;Montecchi, Sarasini 2000;Lenne 2005).
Spores of Octaviania asterosperma have very typical ornamentation in form of large, dense, pyramidal, mostly blunt spines, up to 4 μm high. These become sometimes bent at their apices, and may also coalesce in a small group of 2-4. The study by orihara and co-workers (2010), with the use of electron transmission microscope (TEM), revealed the structure of the ornamentation. The spines were shown to be produced by exosporium, and frequently have internal cavities. They also lack perisporium, which is one of the features that is shared by Octaviania and Chamonixia rolland, but differentiates the genus Octaviania from related Heliogaster orihara & iwase (with one species described from Japan, Heliogaster columellifer (Kobayashi) orihara & iwase, previously placed within Octaviania) (orihara et al. 2010).
Structural aspects of gasterocarps and the development of spores have been studied with the aid of light microscopy by Martín and co-workers (1993). They concluded that the shape of spores as well as the form of ornamentation changes considerably as the spores mature, which could have led to some erroneous descriptions by some authors (and perhaps distinguishing separate species, see Montecchi, Sarasini 2000) . The shape of the immature spores is ellipsoid but changes to round with age. The ornamentation of young spores is in form of isolated warts that elongate and take the shape of acute spines coalescing in mature spores. The authors also found no evidence for the presence of sphaerocysts in the inner layer of the peridium, reported by some authors (e.g., Montecchi, Lazarri 1988). Martín and et al. (1993) found exclusively bisporic basidia in Spanish specimens, similarly to the observations of, e.g., Pegler and co-workers (1993), whereas in Polish specimens 2-4-spored basidia were noticed. However, tetrasporic basidia were mentioned for O. asterosperma also by other authors, e.g., Lange (1956), Pilát (1958, Szemere (1965).
Spiny ornamentation is found in typical O. asterosperma form (O. asterosperma var. asterosperma), however Tulasne and Tulasne (1851) described and illustrated O. asterosperma var. depauperata, which differs in the shape of spores (ellipsoid rather than round) and form of ornamentation (transverse ridges and small blunt warts). This variety was mentioned, e.g., by Szemere (1965) and Pilát (1958), and was found originally in France. recently, it was found also in italy, described and illustrated by Gori (on the web page of a.M.B. Gruppo di Muggia e del carso).
Spores of Octaviania species have frequently been recorded in the fecal pellets of rodents (Bennet, Baxter 1989;Blaschke, Bäumler 1989;Mcintire, carey 1989;claridge, Lindenmayer 1998). The animals are possibly attracted by the odour produced by gasterocarps, and easy to detect in fresh, cut specimens. analysis of rodent feces would probably help to detect more localities of Octaviania as terosperma in Poland, as broadleaved trees forests growing on calcareous (or at least calcium containing) bedrock, suitable habitat for this species, are frequent in southern and central Poland.