(Desm.) von Höhnel
SPOTS randomly distributed on leaves, black, shining, oblong, slightly raised, 0.2-0.6 x 0.4-0.8 mm.
APOTHECIA sessile, 0.5-1.0 x 0.5 mm, present on the upper and lower surfaces of leaves.
Excipulum consists of lateral and bottom excipulum.
Lateral excipulum (le) dark brown (7F5), (17.5-)25.0-37.5(-50.0) µm thick.
Bottom excipulum (be) fawn brown (7E4), (20.0-)25.0-32.5(-37.5) µm thick.
ASCI (ac) clavate, 6.0-7.5 x 50.0-62.5 µm, mainly with four ascospores (as), occasionally with 2-6; greater cell 7.5-10.0 x 2.2-5.0 µm, smaller cell 2.5-5.0 x 2.5-5.0 µm. Neither asci nor ascospores stain in Melzer’s reagent.
DISTRIBUTION AND HABITAT. In Poland, on leaves of A. ptarmica growing in the Myrico-Salicetum auritae and Cirsio-Polygonetum plant associations of the Slowinski National Park (54o45'N, 17o26'E; Adamska 2004; Adamska et al. 1999).
The soil chemical and physical properties of the site harbouring the Cirsio-Polygonetum plant association with A. ptarmica hosting S. ptarmicae were: pH (in H20), 4.4-5.5; N-NO3 (mg L-1), 3.0-5.0; P, 26.0-108.0; K, 13.0-64.0; Ca, 476.0-595.0; Mg, 38.0-79.0; Cl, 33.0-87.0; Na, 38.01-14.0; KCl, 70.0-240.0; org. C (%), 1.83-4.50; bulk density (kg L-1), 0.75-1.50.
The properties of the soil properties from under the Cirsio-Polygonetum plant association where A. ptarmica affected by S. ptarmicae grew were: pH, 3.5-3.9; N-NO3, 3.0-4.1; P, 31.0-85.0; K, 10.0-25.0; Ca, 289.0-374.0; Mg, 43.0-52.0; Cl, 31.0-63.0; Na, 36.0-80.0; KCl, 150.0-380.0; org. C, 1.0-9.12; bulk density 0.55-1.40.
Despite A. ptarmica, the only plant host of S. ptarmicae, occurs commonly in Europe, Asia and North America, this fungus has so far been found only in Europe (Holm 1971). Literature data indicate that S. ptarmicae is an exceptionally infrequently occurring fungus in Europe and Poland is the fifth country in which it was recorded. The specimens of S. ptarmicae examined by Holm (1971) came from France, Germany, and Holland. Moore (1959) listed S. ptarmicae among British parasitic fungi.
NOTES. The genus Schizothyrioma comprises two species, S. aterridium and S. ptarmicae, the latter fungus characterized here. These fungi are hosted only by A. ptarmica and are superficially indistinguishable. The main properties separating the two fungi are the number of spores in an ascus, size of ascospores, and the reactivity of asci in mountants containing iodine. Whereas S. ptarmicae forms asci with 2-6 spores, those of S. aterridium usually contain eight ascospores, occasionally six (Holm 1971). Additionally, the ascospores of the former species are ca. 2-fold wider than those of the latter fungus. Finally, no structure of S. ptarmicae stains in iodine-based mountants, which in S. aterridium takes place and reveals an apical ring (Holm 1971). In contrast, the ascus of S. ptarmicae entirely lacks an apical ring. According to Holm (1971), the differences presented above suggest that S. ptarmicae is a more advanced fungus and was derived from the 8-spored, J+ ascus of S. aterridium.
As mycological literature shows, the position of S. ptarmicae in the classification system of cup fungi changed. This fungus was included in the families Euphiacidieae, Hypodermataceae, and Phiacidiaceae (Holm 1971). According to Holm (1971), the biology, morphological properties of the fruit body, and the characters of spores, asci, and paraphyses of S. ptarmicae suggest it to be a member of the family Pseudopezizoideae. In Ainsworth and Bisby’s Dictionary of the Fungi (Kirk et al. 2001), the genus Schizothyrioma belongs to the family Dermateaceae.
Adamska I. 2004. Schizothyrioma ptarmicae (Helotiales, Ascomycota), a rare European fungus newly found in Poland. Acta Soc. Bot. Pol. 73(1), 57-59.
Adamska I., Madej T., Czerniawska B., Blaszkowski J. 1999. Parasitic and saprotrophic fungi from Slowinski National Park. Acta Mycol. 34, 97-103.
Kirk P. M., Cannon P. F., David J. C., Stalpers J. A. 2001. Ainsworth & Bisby’s dictionary of the fungi. Ninth Edition. CAB International.
Holm L. 1971. Taxonomic notes on Ascomycetes. VII. Schizothyrioma Ptarmicae (Desm.) von Höhnel, and ist double. Svens Bot. Tidskif 65, 208-212.
Moore W. C. 1959. British parasitic fungi. A host-parasite index and a guide to British literature on the fungus diseases of cultivated plants. Cambridge University Press, 430 pp.