Geastrum hansagiense Bóna, Merényi, Boros, Stielow & Bratek, sp. nov.
Index Fungorum number: IF 834968; MycoBank number: MB 834968; Facesoffungi number: FoF 08141; Fig. 1
Etymology – The name refers to a Hungarian area (Hanság), where the type specimen was collected.
Holotype – BP110893
Basidiomata epigeous at maturity. Unexpanded basidiomata subglobose, depressed, 6.6(4–10) mm high, the minimal width 10.4(6–16) mm, the maximal 12(8–19) mm. Expanded basidiomata subglobose, 9.3(5.5–12) mm high, the minimal width 24.5(11–37), the maximal 27.5(20–38) mm, including rays. The outer surface of exoperidium smooth, light brown, silvery shining, vinaceous buff (31) with shade of smoke grey (34), the inner surface of exoperidium darker, date brown (24) under dry condition (Colour Identification Chart of Royal Botanic Garden, Edinburgh (RBGE) 1969). Exoperidium strongly hygroscopic, splitting into 7–9(6–12) triangular rays. Endoperidial body subglobose, saccate, flatted, sessile, distinctly pruinose, 13.2(9.5–19) high and 15.2(11–23) mm wide, light brownish, vinaceous buff (31), clay buff (32), drab (33) (RBGE 1969). Mycelial layer not always visible or intact, white to pale yellow, encrusted with some debris, formed hyaline to quite pale yellow, sinuous hyphae, 4.8(3–9.1) µm diam., thin–walled (<1 µm), lumen evident. Fibrous layer papery, compact, persistent, yellowish to brownish, formed yellowish, sinuous hyphae, 4.4(3–6.5) µm diam., thin–walled (<1 µm), lumen evident. Pseudoparenchymatous layer persistent, yellowish, with irregular subglobose to ellipsoid hyphal cells, in various shapes and size, 21.2(12.5–37.1) µm long and 14.4(8–26.7) µm wide, with 1.5(0.5–2.5) µm wall. Stalk absent. Apophysis absent. Peristome undelimited, almost flat to slightly elevated, mammiform, tenderly fibrillose, closed or opened with age, with irregularly shaped pores, similar or lighter than the endoperidium, milky coffee (28) or fawn (29) (RBGE 1969), but seems too darker because of the effused basidiospores. Columella central, pyramid shape, often imperceptible, light brown, clay buff (32) (RBGE 1969). Mature gleba forcibly dark brown to blackish, fuscous black (36) (RBGE 1969). Basidiospores globose, brownish or dark brown in 5% KOH, 5.7(4.9–7.1) µm diam. with verrucose ornamentation. Basidia not seen. Eucapillitium sinuous, 5.9(3.5–8) µm diam., rarely verrucosed, unbranched, thin–walled (≤1 µm), lumen evident.
Habit and habitat – Hundreds of specimens were found in a small, few m2 area. The habitat of G. hansagiense is a ruderal nitrogen–rich grassland (dominant plant species Galium aparine, Conium maculatum, Urtica dioica) with nutritious soils.
Distribution – Specimens were found near to Mosonmagyaróvár (47°50′22.3″ N 17°14′30.1″ E), Hanság–area, Hungary. The formerly drained sweetwater turf marshland, Hanság–area is situated in the Little Hungarian Plain and closely connected with the westernmost Salt Lake of Eurasia, Lake Neusiedl. Until now the known distribution is restricted to the locus classicus.
Material examined – HUNGARY, Hanság–area, Mosonmagyaróvár, 47°50′22.3″ N 17°14′30.1″ E, on a ruderal nitrogen–rich grassland, 17 October 2015, L. Boros (BP110893, holotype).
GenBank numbers – ITS = MN582753, MN582754, LSU=MN582739.
Notes – Macromorphological descriptions based on ca. 30 fruitbodies in different developmental stages. Geastrum hansagiense is recognized by depressed, flatted, subglobose, usually wider than higher basidiomata, distinctly pruinose, sessile endoperidial body, tenderly fibrillose, mammiform, undelimited peristome, hygroscopic exoperidium, lacking of the stalk and apophysis and almost black gleba with globose, verrucose basidiospores (Fig. 1). One species with nearly identical characters is G. floriforme. Geastrum hansagiense is differentiated from G. floriforme by the size of the basidiomata, since the unexpanded G. floriforme basidiomata is 8.5 mm wide, the expanded basidiomata 21.5 mm wide and the endoperidial body 8.8 mm wide on average, based on our own mesurements and data from the literature (Hollós 1903; Jeppson et al. 2013; Sousa et al. 2014). Similarly, hygroscopic and sessile species are in genus Geastrum, G. kotlabae, G. corollinum and G. hungaricum, but their peristomes are totally different. Geastrum hansagiense is presumably a pseudocryptic species in the absence of remarkable morphological differences from G. floriforme. However, G. hansagiense differs from G. floriforme in some unique fixed alleles of the ITS locus, based on the alignments of sequences (Fig. 2). Geastrum hansagiense’s unique fixed alleles are: 14(T), 16(A), 17(G), 18(A), 19(T), 21(A), 22(G), 23(A), 26(G), 41(C), 43(gap), 46–48(gap), 62(T), 72(C), 111–112(A), 119(T), 125(C), 127–128(T), 152(A), 155–156(gap), 158(gap), 159(G), 160(T), 176–178(A), 179(T), 180(A), 184(T), 348(C), 362–363(T), 370(A), 375(G), 382(C), 387(A), 394(C), 395(G), 405(G), 411(C), 432(C), 463(gap), 468(T), 478(T), 492(A), 493(T), 505(C), 510(gap), 513–514(gap), 522(T), 534(G).
Figure 1 – Geastrum hansagiense (BP110893, holotype). a Habitat of G. hansagiense. b Basidiomata. c Columella. d Peristome. e Basidiospore under SEM f Basidiospores and eucapillitium under LM. Scale bars: e=1 µm, f=6 µm
Figure 2 – Maximum likelihood (ML) phylogenetic tree of Geastrum species derived from concatenated internal transcribed spacer (ITS) and 28S rRNA (LSU) regions. Analysis was performed by RAxML under GTR+GAMMA model. Myriostoma coliforme (KC582020) is selected as the outgroup taxon. ML bootstrap values were obtained from 1000 replicates and values greater than 70% were indicated. The scale bar represents 0.007 expected nucleotide changes per site. The novel species are in blue, holotype specimen is in bold, herbarium numbers and NCBI Accession Numbers in brackets