Oxydothis calamicola Konta & K.D. Hyde, in Konta, Hongsanan, Tibpromma, Thongbai, Maharachchikumbura, Bahkali, Hyde & Boonmee, Mycosphere 7(9): 1432 (2016)

Index Fungorum number: IF552542; Facesoffungi number: FoF

Etymology – The specific epithet refers to the host genus Calamus, and cola meaning loving.

Saprobic on rachis of Calamus L. (Arecaceae). Sexual morph: Ascomata 280–835 μm diam. (x̅ = 673 μm diam., n = 40, up to 1,700 μm), solitary or aggregated, mostly solitary when young, becoming grouped at maturity, immersed, comprising non-blistering areas through the host tissue, axis oblique or perpendicular to the host surface, with central papilla, 30–46 μm high × 186–230 μm diam. (x̅ = 35 × 222 μm, n = 5), in transverse section, lenticular, globose to subglobose, darker at the central region, light towards the outer darker rim on the host surface. Peridium 8–15 μm (x̅ = 11μm, n = 10), outer cells merging with the host epidermal cells, comprising dark brown to black, walled cells of textura angularis. Asci 142–150 × 8–11 μm (x̅ = 144 × 10 μm, n = 10), 8-spored, unitunicate, cylindrical, pedicellate, with a J+, wedge-shaped, subapical ring. Ascospores 48–50 × 4–5 μm (x̅ = 48 × 5 μm, n = 20), 1–2-seriate, fusiform, tapering gradually from the center to the ends, centrally 1-septate, not constricted at the septum, with pointed ends, hyaline, with one large guttules at the central when immature, becoming two large guttules when mature in each cell, smooth-walled. Asexual morph: Undetermined. Appressoria not formed.

Culture characters – Ascospores germinating on MEA within 24 hours. Colonies on MEA, grey to olivaceous, surface rough, margins smooth, produced rudimentary ascomata, hyphae, septate, branched, smooth-walled (Fig. 9 viz a).

Material examined – Thailand, Chiang Mai, on the dead rachis of Calamus L. (Arecaceae), 11 August 2014, S. Konta, P04c (MFLU 15-0016, holotype); Ibid. (HKAS95039, isotype); ex-type living culture, MFLUCC 14-1165.

NotesOxydothis calamicola is similar to O. maculosa Penz. & Sacc. in its ellipsoidal ascomata in the transverse section, as well as the shape and size of ascospores. Oxydothis calamicola differs from O. maculosa in forming globose to subglobose rims on the host surface, with dark ostiolar dots at the center, while O. maculosa forms blackened regions on the host surface. Phylogenetically, Oxydothis calamicola is placed in a basal clade to O. palmicola and O. metroxylinicola. Oxydothis calamicola is distinct from these two species in having smaller ascomata and ascospores with spine-like ends.

Fig 1. Oxydothis calamicola (holotype) a. Appearance of fruiting bodies on host substrate. b–c. Close-up of fruiting bodies. d. Section of ascoma. e. Peridium. f–k. Asci. l. J+ reaction of the apical ring in Melzer’s reagent. m. Germinating ascospore. n–s. Ascospores. Scale bars: a = 500 μm, b–c = 200 μm d = 50 μm, e–l = 20 μm, m–s = 10 μm.