Roesleria subterranea (Weinm.) Redhead, Can. J. Bot. 62: 2516, 1984.

Degawa, Yousuke, Hosoya, Tsuyoshi, Hosaka, Kentaro, Hirayama, Yumiko, Saito, Yukiko & Zhao, Yan-Jie, 2015, Rediscovery of Roesleriasubterranea from Japan with a discussion of its infraspecific relationships detected using molecular analysis, MycoKeys 9, pp. 1-9 : 3-5

Taxon classification Fungi incertae sedis Roesleriaceae

Roesleria subterranea (Weinm.) Redhead, Can. J. Bot. 62: 2516, 1984. Figs 1, 2

Pilacre subterranea ? Weinm., Flora 15 (Beiblatt, Bd. 1), p. 458, 1832.

Note.

For the detailed synonymy, see Redhead (1984).

Discription.

Apothecia capitate, long-stalked, 0.5-1.5 mm high, hypogeous, on plant root; head spherical to irregular, 0.4 mm diam., composed of dried spore mass (mazaedia), powdery, grayish green (C16M0Y36K0); stalk 0.1 mm diam., base of apothecium with elongated cells (7-13 ? 2.5-4.5 ?m), pale-colored; ectal excipulum not observed due to maturation of apothecia. Asci 40-55 ? 6.5-7.0 ?m, cylindrical-clavate, thin walled, arising from croziers, eight-spored, evanescent, releasing ascospores by degradation of ascal wall; apex rounded, Meltzer reaction– with or without KOH pretreatment. Ascospores 5-6.4 ? 4.5-5.5 ?m, broadly elliptical, almost hyaline, pale-colored to dark-colored due to maturation, aseptate when young, becoming almost spherical to lenticular, transversely one-septate. Germination tubes usually occur from each cell of ascospores. Paraphyses cylindrical, simple, straight to waving, enlarged toward apex up to 6-?m wide, multiseptate, often long, extending beyond asci. Ascospores germinated on CMA, MEA, and MEYE to produce mycelium. On PDA, colonies of 65 mm diam in 30 days at 23 C, surface floccose; aerial mycelium well-developed at center, white; substratal mycelium dark green (C24M5Y98K35), becoming paler (C10M0Y54K0) toward the margin. Colonies were dark green (C24M0Y98K8) from the reverse, producing stronger colored patches, paler (C6M0Y54K0) toward margin. On MEA, colonies 65 mm diam in 30 days at 23 C, surface floccose; aerial mycelium well developed, light green (C10M0Y72K0) at center, becoming sparse and paler (C6M0Y54K0) toward margin; substratal mycelium obscured. Colonies dark green (C20M4K100Y32) at center from reverse, becoming paler (C6M0Y54K0) toward margin. On CMA, colonies 60 mm diam in 30 days at 23 C, mycelium sparse, with almost no coloration. Asexual state not observed in culture.

Specimens examined.

Japan. Nagano Prefecture: Pinus densiflora forests approximately 30 years old, Sugadaira Montane Research Center, University of Tsukuba, Ueda (36°52.12'N, 138°34.97'E (DDM)), ca 1300-1360 m, 19 Nov 2010, Y. Degawa (TNS-F-38701), on unknown deciduous plant roots (not Vitis ), multi-ascospore isolate FC-2678 (NBRC108276). Hokkaido isl., Sapporo: 20 Aug 1922, K. Togashi (TNS-F-185301) as Calicium pallidum , on Vitis vinifera . Iwate Prefecture: Morioka, Oct 1935, "College Orchard", “Murata” (TNS-F-185302) as Calicium pallidum , on Vitis vinifera (The words with double quotation indicate the data written on the original specimen label. The precise information is unclear, as this specimen was donated to TNS by K. Togashi.).

The specimen collected at Sugadaira showed similar morphological agreement with previous reports ( Redhead 1984, Yao and Spooner 1999, Kirchmair et al. 2008). The taxonomy of Roesleria subterranea , however, has been under debate. It was suggested to belong to Caliciaceae , Caliciales ( Redhead 1984). Yao and Spooner (1999) proposed Roesleriaceae , but its placement was not mentioned by Kirk et al. (2008). Based on the molecular phylogeny on rDNA, it was classified as Helotiaceae , but Roesleriaceae as a distinct family has not been ruled out ( Kirchmair et al. 2008, Neuhauser et al. 2011).

Two other genera are known for their occurrence on plant roots. One is Moserella Poder & Scheuer, known as a root endophyte of Picea , and the other is Roeslerina Redhead, obtained from coniferous roots ( Redhead 1984, Yao and Spooner 1999). Because these two genera and Roesleria have mazaedia, mazaedia formation may be suggested to be a common convergent character in hypogeous apothecial fungi.

We found two specimens (TNS-F-185301 and 185302) of Roesleria subterranea deposited in TNS as Calicium pallidum , which were reported by Togashi (1950). Although Calicium pallidum is a lichen name, it is also a misapplied name for Roesleria subterranea . We did not attempt DNA extract analysis of TNS-F-185301 and TNS-F-185302 because the specimens lacked sufficient material to guarantee a DNA, and in our experience, such DNA is damaged due to repeated fumigation.