Melanconis groenlandica (M. Bohn) L. Lombard & Crous, in Lombard et al. Persoonia 36: 234 (2016).

Jaklitsch, Walter M. & Voglmayr, Hermann, 2020, The genus Melanconis (Diaporthales), MycoKeys 63, pp. 69-117 : 69

Melanconis groenlandica (M. Bohn) L. Lombard & Crous, in Lombard et al. Persoonia 36: 234 (2016).

≡ Myrothecium groenlandicum M. Bohn, Mycotaxon 46: 336 (1993) (Basionym).

Type material.

Holotype (not examined): Greenland, Qaqortoq, (isolated from) twigs of Betula nana , July 1991, M. Bohn (C; dried culture UPSC 3416; isotype in UPS; living cultures CBS 116450 = UPSC 3407, UPSC 3416).

Description

(after Bohn 1993): Colonies on PDA and MEA 30-33 mm after 10 d (52-62 mm after 20 d), appearing leathery, at first whitish to greyish, later becoming greyish-orange, particularly on MEA; margin superficial, entire on MEA but fimbriate to lobate on PDA; exudate and diffusible pigment absent; reverse greyish-orange, especially at the margin; brownish, thick-walled, chlamydospore-like swollen portions 6-18 µm diam. present. Conidiomata appearing after ca. 14 d as dark green pustules of various sizes, irregularly scattered over the colony surface, but sometimes arranged in concentric rings, particularly in old cultures, initially covered by mycelium but becoming almost black and shiny at later stages due to the mass of conidia; conidiomata sporodochial (acervular?), irregular, dark green, up to 2 mm diam., scattered, gregarious or coalescent, composed of a 50-70 µm high stroma of textura intricata and conidiophores. Marginal hyphae and setae absent. Conidiophores arising from the stroma, branched, septate, yellowish to brownish, ca. 40-75 µm × 2-4 µm. Conidiogenous cells cylindrical to subulate, 15-25 × 2-3 µm, arranged in verticils of 2-4 at the top of the conidiophore, sometimes also intercalary, provided with conspicuous, pigmented collarettes and producing conidia by percurrent growth. Conidia black and shiny in mass, olivaceous to brownish under the microscope, straight, cylindrical with rounded ends, sometimes slightly narrowing towards the base or apiculate, (9-)10-12(-15) × (5-)6(-7) µm, with smooth wall. Teleomorph not formed after 3 months incubation.

Culture (own observations): Colony on MEA circular, first hyaline, turning and long remaining whitish, with age forming narrow concentric zones with tooth-like margins and turning pale brownish. Odour indistinct to unpleasant.

Distribution and ecology.

Melanconis groenlandica is known from North America (Greenland, USA) and Japan from Betula maximowicziana , B. nana and B. papyrifera .

Additional collections sequenced.

Japan, Hokkaido, Sorachi, Furano, Hokkaido Experimental Forest of Univ. Tokyo, on B. maximowicziana , 25 Sep 1964, T. Kobayashi (TFM FPH2478, culture MAFF 410219 = M4-2, ME1). USA: New Hampshire, close to the top of Mount Washington, on Betula sp., 28 Jul 2006, L. Mejia (BPI 879597; culture CBS 133339 = LCM 02.02 = ME13); New York, Adirondack High Peaks Region, Marcy Dam, on Betula papyrifera , 2 Jun 2007, L. Mejia (BPI 881485; culture CBS 133341 = LCM191.01 = ME10); ibidem, same host, 9 Jun 2007, L. Mejia (BPI 881515; culture CBS 133340 = LCM 185.01).

Note.

This species was isolated as a putative endophyte from Betula nana and described from MEA and potato dextrose agar as a species of Myrothecium . In our phylogenetic analyses, three isolates from North America and one from Japan grouped with the ex-type isolate of M. groenlandica with high support.