Arthrinium hysterinum (Sacc.) P.M. Kirk, Trans. Brit. Mycol. Soc. 86: 409 (1986)

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 hysterinum (Sacc.) P.M. Kirk, Trans. Brit. Mycol. Soc. 86: 409 (1986) Fig. 8

Melanconium hysterinum Sacc., Bolm Soc. broteriana, Coimbra, sér. 1 11: 21 (1893) [Basionym].

Scyphospora hysterina (Sacc.) Sivan., Trans. Brit. Mycol. Soc. 81: 331 (1983).

Melanconium bambusae Turconi, Atti Ist. bot. R. Univ. Pavia, sér. 2 16: 251 (1916).

Scirrhia bambusae Turconi, Atti Ist. bot. R. Univ. Pavia, sér. 2 16: 531 (1916).

Scirrhodothis bambusae (Turconi) Trotter, in Saccardo, Syll. Fung. 24: 611 (1926).

Placostroma bambusae (Turconi) R. Sprague, Diseases Cereals Grasses N. Amer.: 121 (1950).

Apiospora bambusae (Turconi) Sivan., Trans. Brit. Mycol. Soc. 81: 331 (1983).

Scyphospora phyllostachydis L.A. Kantsch., Bolêz. Rast. 17: 88 (1928).

Cordella johnstonii M.B. Ellis, Mycol. Pap. 103: 31 (1965).

Apiospora setosa Samuels et al., New Zealand J. Bot. 19: 142 (1981).

Apiospora tintinnabula Samuels et al., New Zealand J. Bot. 19: 142 (1981).

Description.

Sexual morph: Stromata black, fusiform, forming rows of densely arranged perithecial ascomata parallel to the main axis of the host, measuring (400-) 600 –2500(– 3000) × (250 –)320–450(– 550) µm (n = 30). Ascomata globose to subglobose, with a flattened base, blackish brown, (130 –)250–290(– 320) µm in diameter (n = 30). Peridium consisting of 3 or 4 layers of cells arranged in textura angularis, dark brown in the external side, hyaline in the inside, ostiole single, central, 10-30 µm in diameter, with a periphysate channel 20-35 µm long. Peryphises broad, colourless. Hamathecium composed of dense hypha-like, broad septate paraphyses, early deliquescing. Asci 8-spored, unitunicate, clavate, broadly cylindrical, pedicel indistinct, apical rounded, thin-walled, without an apical apparatus, measuring (76-) 85 –98(– 115) × (20 –)22–26(– 28) µm (n = 22). Ascospores uni- to tri-seriate, hyaline, apiosporic, smooth-walled, fusiform, elliptical, reniform, straight or curved, smooth-walled, sometimes with an internal droplet, bicellular, the widest part located in the central part of the longest cell, some ascospores have a mucose sheath covering them, (28 –)32–34(– 38) × (8 –)9–11(– 13) (n = 35) µm, basal cell 5-7 µm. Asexual morph: Mycelium branched, septate. Conidiomata on host surrounding the stromata of the sexual phase, parallel to the longitudinal axis of the stem, subepidermal, opening by longitudinal splitting of the epidermis and revealing a black conidial mass, (450-) 630 –950(– 1000) × (275 –)345– 550 (-600) µm (n = 35). Conidiophore mother cell arising from the stroma, ampuliform, lageniform, cupulate or cylindrical, sometimes with granular pigments at the apex, (5)6 –10(– 16) × (3 –)5–7(– 8) µm (n = 24). Conidiophores basauxic, polyblastic, cylindrical, hyaline to light brown, smooth or with granular pigments in all their length, straight or flexuous, septate or not, sometimes exceeding 90 μm in length × 2-4 μm wide (n = 43). Conidia globose to obovoid, dark brown, with a central scar at the base, (15 –)16–20(– 21) in frontal view, (14 –)15–18(– 19) in side view (n = 40). Sterile cells gray, irregularly angled and lobed, (15 –)17–41(– 42) × (10 –)14–23(– 25) µm (n = 30). Culture characteristics: colonies in MEA 2% flat, spreading, first white and cottony, later became dark pink, mycelium branched, septate, hyaline, reverse dark.

Notes.

After the works of Samuels (1981), Sivanesan (1983), Kirk (1986) and Réblová et al. (2016), Ap. bambusae , Ap. setosa and Ap. tintinnabula , as well as Scyphospora phyllostachydis , are all considered synonyms of A. hysterinum . Arthrinium hysterinum is phyllogenetically close to A. yunnanum D.Q. Dai & K.D. Hyde, but morphologically differs from the latter because of its thinner asci (76-115 × 20-28 vs 85-100 × 30-35 μm). In addition, A. hysterinum has longer conidiophores up to 90 μm long, and lobed sterile cells while in A. yunnanum conidiophores do not exceed 50 μm, and sterile cells are lacking.

Specimens examined.

New Zealand: Waikato: Paeroa, on dead culm of Bambusa sp., 28 Feb. 1980, E.H.C. McKenzie & P.R. Johnston (ICMP 6889 ex-type culture).

Spain: Galicia: Santiago de Compostela, on dead culms of Phyllostachys aurea , 12 Jan. 2018, A. Pintos (MA-Fungi 91731, AP12118). Balearic Islands: Mallorca, Esporlas, on dead culms of Phyllostachys aurea , 29 July 2017, A. Pintos (MA-Fungi 91729, AP29717). Mallorca, Jardin Botanico de Soller, on dead culms of Phyllostachys aurea , 24 Oct. 2017, A. Pintos (MA-Fungi 91730, AP2410173). Mallorca, Soller, on dead culms of Phyllostachys aurea , 15 Mar. 2018, A. Pintos (MA-Fungi 91728, AP15318).