Arthrinium curvatum var. minus M.B. Ellis, Trans. Brit. Mycol. Soc. 34: 501 (1951) Fig. 5

Physalospora scirpi Arx, Gen. Fungi Sporul. Cult. (Lehr): 116 (1970).

Pseudoguignardia scirpi Gutner, Mater. Mikol. Fitopat. Ross. 6(1): 311 (1927).

Description.

Asexual morph: Colonies are compact, round, dark to black, 80-320 in diameter. Mycelium is composed of hyaline to pale brown smooth hyphae 2-7 µm in diameter. Conidiophore mother cells spherical to lageniform, hyaline with brown pigments at the base, measuring (4 –)5–7(– 8) × (4 –)5–6(– 7) µm (n = 30). Conidiophores cylindrical unbranched, straight or flexuous, hyaline and smooth walled, with a single brown transversal septa, measuring 30-100 × 2-4 µm . (n = 30). Conidiogenous cells cylindrical 1-1.5 × 1-1.5 µm (n = 20). Conidia borne along the sides of conidiophores, curved, rounded at the ends, brown, with a hyaline germ slit and a clearly visible scar, (8 –)9–10(– 11) µm long in frontal view, (5 –)6–7(– 8) µm in side view (n = 30). Sterile cells rounded, paler than conidia. Culture characteristics flat colonies spreading on MEA 2% with moderate aerial mycelium, reverse withish.

Notes.

Arthrinium curvatum var. minus can be confused with A. curvatum var. curvatum, but conidia of var. minus measure (8 –)9–10(– 11) × (5 –)6–7(– 8) µm, while those of A. curvatum var. curvatum measure 11-15 × 6-8 µm . Gutner (1927) described Pseudoguignardia scirpi, a sexual morph of A. curvatum, later combined as Physalospora scirpi (Arx 1970). Arthrinium curvatum var. minus is closely related with A. sporophleum (with lemon-shaped conidia) and A. japonicum (with larger fusiform conidia) and to a lesser extent also with A. caricicola (with larger fusiform conidia) and A. puccinioides (with polygonal conidia). Ellis et al. (1951) described A. curvatum var. minus, a taxon with similarly shaped but smaller conidia than A. curvatum . The specimen studied in the present work matches the shape and size of conidia reported by Ellis et al. (1951) for A. curvatum var. minus, rather than those of A. curvatum var. curvatum .

Specimens examined.

Germany: Brandenburg: south of Liberose, on dead leaves of Carex sp., 28 Mar. 2018, R. Jarling (MA-Fungi 91726).