Arthrinium marii Larrondo & Calvo, Mycologia 82: 397 (1990)

Pintos, Angel, Alvarado, Pablo, Planas, Juan & Jarling, Rene, 2019, Six new species of Arthrinium from Europe and notes about A. caricicola and other species found in Carex spp. hosts, MycoKeys 49, pp. 15-48 : 15

Arthrinium marii Larrondo & Calvo, Mycologia 82: 397 (1990) Fig. 11

Description.

Sexual morph: Stromata forming black fusiform spots, visible at the naked eye, with a long axis broken at the top revealing the ostioles of pseudothecia, 2-6 × 0.2-0.5 mm in size. Ascomata subglobose, sometimes with a flattened base, brownish to reddish brown, 150-190 μm high × 160-250 μm wide (n = 20). Peridium with several layers of cells arranged in textura angularis, with a conspicuous ostiole 50 –7– 80 μm diameter, periphysate. Hamathecium paraphyses not prominent, hyphae-like, septate, hyaline. Asci 8-spored, unitunicate, broadly cylindrical to clavate, with rounded apex and a short pedicel, (60 –)70–100(– 115) × (16 –)18–20(– 22) μm (n = 30). Ascospores fusiform to elliptical, with narrowly rounded ends, hyaline, with multiple guttules, surrounded by a mucilaginous sheath, (16)19 –23(– 24) × (6 –)7–8(– 10) μm, basal cell 2-5 (n = 30). Asexual morph: Mycelium consisting of smooth, hyaline, branched, septate hyphae measuring 1.5-5 µm in diameter. Conidiophores straight or flexuous, cylindrical, colourless except for the thick brown transverse septa, measuring 10-40 × 2-3 μm. Conidiogenous cells ampuliform to cylindrical, hyaline to brown, (3 –)4–7(– 11) × (1.4 –)2–4(– 5) μm (n = 30). Conidia, brown, smooth, granular, globose in face view, lenticular in side view, measuring (6 –)7–8(– 9) × 4 –5(– 6) µm, with a pale equatorial slit. Sterile cells elongated, brown. Culture characteristics: ascospores germinating on MEA 2% within 24-48 h. Colonies flat, spreading, with sparse aerial mycelium, reverse concolour with agA.

Notes.

Arthrinium marii was proposed by Larrondo and Calvo (1990) who described its asexual morph. This apparently frequent species has been isolated from the atmosphere, pharmaceutical excipients, home dust, and beach sand, as well as from various plant hosts (Crous 2013). In the present work the sexual morph is described for the first time. Genetically, samples identified as A. marii seem to represent two distinct clades (Fig. 2), with differences in tub2 and tef1 genes, but it should be further investigated with additional data before concluding if these clades should be interpreted as intraspecific variability, partially isolated lineages, or fully isolated species. Similarly, the incomplete data from the type specimens of A. hispanicum and A. mediterranei do not allow one to conclude if these apparently related species represent a single taxon or even belong to A. marii .

Specimens examined.

Austria: Oberösterreich: St. Willibald, on dead culms of Phragmites australis , 10 July 2016, H. Voglmayr, (MA-Fungi 91738, AP191017).

Italy: Sicily: casa de la Monache, on dead culms of Phragmites australis , 16 July 2016, H. Voglmayr (MA-Fung 91740, APVog2).

Portugal: Viana do Castelo: Valença do Minho, on dead culms of Phragmites australis , 10 Jan. 2018, A. Pintos (AP10118A).

Spain: Balearic Islands: Mallorca, Esporlas, on dead culms of Arundo donax , 13 July 2017, A. Pintos (MA-Fungi 91735, AP13717). Ibidem., 29 July 2017, A. Pintos (AP29717). Palma de Mallorca, on Ampelodesmos mauritanicus , 11 July 2017, A. Pintos (MA-Fungi 91737, AP11717A). Palma de Mallorca, on dead culms of Phragmites australis , 26 July 2017, A. Pintos (MA-Fungi 91739, AP261017).