Arthrinium italicum Pintos & P. Alvarado

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 italicum Pintos & P. Alvarado sp. nov. Fig. 10

Etymology.

In reference to Italy, the country where the holotype was found.

Diagnosis.

Sexual morph: Stromata solitary to gregarious, inmersed to erumpent, fusiform, with long axis broken at the top by one or two cracks, 0.5-4 × 0.2-0.5 mm (n = 20). Ascomata uniseriate or irregularly arranged beneath stromata, pseudothecial, black, globose to subglobose with a flattened base, 150-200 μm high × 230-300 μm wide. Peridium composed of 5 or 6 layers of brown cells arranged in textura angularis, with a conspicuous peryphisate ostiole. Hamathecium paraphyses hyphae-like. Asci broadly cylindrical, clavate or subglobose, pedicel indistinct, apically rounded (70 –)72–93(– 96) × (14 –)15–18(– 20) μm (n = 30). Ascospores apiosporic, clavate to fusiform with narrowly rounded ends, composed of a large upper cell and small lower cell, hyaline, smooth-walled, surrounded by a gelatinose sheath, measuring (20 –)21–25(– 26) × (5 –)6– 9(-10) μm, basal cell 3-5 μm (n = 45). Asexual morph: Mycelium consisting of smooth, hyaline, branched, septate hyphae 1.5-4 µm in diameter. Conidiophores straight or flexuous, cylindrical, colourless except for the thick brown transversal septa, smooth-walled, 10-50 × 1-3 μm. Conidiogenous cells ampuliform, cylindrical or doliform, hyaline to brown, (3 –)4–7(– 9) × (1.5 –)2–3(– 5) μm (n = 30). Conidia brown, smooth, globose in face view, lenticular in side view, 4-6 × 3-4 μm (n = 65), with a pale equatorial slit. Culture characteristics: on MEA 2%, sparse aerial mycelia, surface dirty white, reverse pale yellowish.

Type.

Italy: Sicily: On dead culms of Arundo donax , 19 June 2016, H. Voglmayr (MA-Fungi 91733 holotype, AP221017 isotype, CBS 145138 ex-type culture).

Notes.

Arthrinium italicum is phylogenetically close to A. thailandicum , and to a lesser extent to A. malaysianum . Stromata of A. thailandicum are smaller than those of A. italicum , measuring 0.45-0.99 × 0.3-0.55 mm, ascomata are perithecical, its conidiogenous cells are longer (11.5-39 × 2-3.5 μm) and branched, and conidia measure 5-9 × 5-8 μm. The conidia of A. malaysianum are similar in size, but this species does not produce conidiophores.

Other specimens examined.

Spain: Balearic Islands: Mallorca, Puerto de Andratx, on dead culms of Phragmites australis , 29 Jan. 2018, A. Pintos (MA-Fungi 91734, AP29118).