Creosphaeria sassafras (Schwein.: Fr.) Y.-M. Ju, F. San Martin,
and J. D. Rogers.
Stromata erumpent to nearly superficial, with abrupt margins, containing
one to few perithecia, frequently coalescent in linear rows, 1.5-15 mm long
x 1-1.5 mm broad x 1.1-1.6 mm thick; surface dull black, waxy, roughened, flattened
at the top, somewhat depressed and paler around the ostioles, with inconspicuous
perithecial mounds; the tissue between the perithecia waxy, orange to black mixed with
orange granules, with KOH-extractable pigments orange; the tissue below the
perithecia black, inconspicuous. Perithecia subglobose 0.9-1.1 mm diam,
to broadly cylindrical under mutual pressure 0.5-0.7 mm diam x 0.9-1 mm high,
with ostiolar canal lined with whitish material. Ostioles umbilicate
or at the same level as stromatal surface, usually at the centre of a grey
pruinose disc 60 µm diam. Asci cylindrical, long-stipitate, with a discoid,
amyloid apical ring 0.7-1 µm high x 2-2.7 µm broad. Ascospores light
brown to brown, ellipsoid slightly inequilateral to oblong or cylindrical, 8.8-11.5
x 3-4 µm, with straight germ slit spore-length on the more convex side when
inequilateral; perispore indehiscent in 10% KOH, smooth.
Specimens examined: FRANCE: Ariège (09): Rimont, Las Muros, ruisseau
de Peyrau, 15 Jul. 2002, JF-02124, on Ulmus minor. Pyrénées Atlantiques
(64): Oloron Ste. Marie, Forêt de Bugangue, 05 Oct. 1997, FC-5231-97, on Fraxinus
excelsior; Oloron Ste. Marie, Forêt de Bugangue, 26 Oct. 1998, JF-98160,
on Fraxinus excelsior.
Notes: Creosphaeria sassafras is easily recognized in the field
through its erumpent habit and small stromata in linear rows with a flattened
top and greyish ostiolar area. Identification will be confirmed by the
presence of orange granules inside the stroma and frequently oblong ascospores.
Creosphaeria sassafras is widespread and reported from
Brazil, Canada, Chile, France, Italy, Taiwan, U. S. A. (Miller, 1961;
et al., 1993). Miller (1961) considered it grows exclusively on
Lauraceae (Benzoin, Laurus, Persea, Sassafras) in U. S. A. European
collections show that it may have a wider host range. It is noteworthy that
C. sassafras has been isolated as endophyte from living trees and shrubs such as
Baccharis halimifolia, Platanus occidentalis and Lindera benzoin from U. S. A.
(Bills and Peláez, 1996). French collections were
made on decorticated wood of branches that are not in contact with the soil, in locations
with a high level of moisture. Creosphaeria sassafras seems to be rare in
Europe or rarely reported.