Sphaerellopsis filum (Biv.) B. Sutton, Mycol. Pap. 141: 196 (1977)

Basionym: Sphaeria filum Biv., Stirp. Rar. Sic. 3: 12 (1815)

= Sphaerellopsis quercuum Cooke, Grevillea 12 (61): 23 (1883)

Saprobic or parasiticditto in terrestrial habitats.Sexual morph: undetermined. Asexual morph: Conidiomata 300 μm diam., pycnidial, erumpent, aggregated, globose, dark brown with a central ostiole, exuding copious amounts of creamy orange conidia. Conidiomata wall composed of 3–6 layers of dark brown cells of textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 5–10 × 3–5 μm, brown, smooth, and thick-walled, ampulliform, to doliiform, with prominent periclinal thickening or several prominent, flaring, percurrent proliferations at the apex. Conidia (11–)14–16(–18) × (3–)4(–5) μm, hyaline, smooth-walled, guttulate, fusoid to fusoid-ellipsoid, 1(–2)-septate, usually constricted at septa, apex subobtuse, tapering at the base with a flattened scar, with funnel-shaped, mucoid appendages at each end (from Trakunyingcharoen et al. 2014).

Fig .Sphaerellopsis filum(redrawn from Sutton 1980, Fig 278).a. Conidia. b. Conidiophores and developing conidia. c. Sections of conidiomata.Scale bars: a–b = 10 µm, c = 25 µm

Notes: The genus Sphaerellopsis was introduced by Sutton (1977) and is typified with S. filum (basionym; Sphaeria filum).Species of Sphaerellopsis are well-known mycoparasites occurring on a wide range of rusts and play a potential role as biocontrol agents (Trakunyingcharoen et al. 2014).The asexual and sexual morph connection between Eudarluca caricis, the generic type of Eudarluca and Sphaerellopsis filum was derived from ascospores growing on Puccinia extensicola-oenotherae (Mont.) Arthur on Carex sp. in Pennsylvania, USA (Keener 1951) and confirmed by Yuan et al. (1998). Yuan et al. (1998) grew ascospores of Eudarluca caricis on PDA and derived Sphaerellopsis conidia and conidiomata after 12 days. Zhang et al. (2012) suggested that Eudarluca caricis is compatible with Leptosphaeria species and mentioned that Eudarluca should be treated in Leptosphaeriaceae based on DNA sequence data and also morphological characters. Phookamsak et al. (2014) tentatively placed Eudarluca in Phaeosphaeriaceae based on its morphological characters which are typical of Phaeosphaeria as the peridium is thin-walled, and composed of pseudoparenchymatous cells, asci are cylindrical, subsessile to short pedicellate and ascospores are fusiform and phragmosporous.