(Biv.-Bern. ex Fr.) Sutton
PYCNIDIA (p) globose, subglobose to egg-shaped, dark brown to brownish black, erumpent, rarely immersed, subepidermal, separate, unilocular, up to 200 µm diam, with a subcircular to elliptical ostiolum, 20-30 µm diam, formed in uredinia of species of the order Uredinales.
Wall (w) 6-16 µm thick, composed of thick-walled, dark brown, angular cells near the ostiolum, and less pigmented, thin-walled cells below the ostiolum.
CONIDIA (c) hyaline to pale brown, ellipsoidal to cylindrical, sometimes slightly curved, smooth, 0-1-septate, sometimes slightly constricted at the septum, 13-19.5 x 2.2-6.5 µm, formed on hyaline, short, obpyriform to doliiform, enteroblastic, phialidic conidiogenous cells (cc) lining the inner surface of the pycnidial wall.
HOST AND DISTRIBUTION. The hosts of S. filum are different fungal species of the order Uredinales (Sutton 1980).
Sphaerellopsis filum is worldwide in distribution (Sutton 1980).
NOTES. The teleomorph of S. filum is Eudarluca caricis (Fr.) Eriksson.
Sutton B. C. 1980. The Coelomycetes. Fungi imperfecti with pycnidia, acervuli, and stromata. Commonwealth Mycological Institute. Kew, Surrey, England.