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Entoleuca mammata (Wahlenberg: Fr.) Rogers & Ju.
For synonyms, the reader is referred to Miller (1961)
or Rogers and Ju (1996).
Stromata erumpent, orbicular (3-8 mm diam) to elongate 5-12 mm long
x 3-5 mm broad x 2-4 mm thick, uni- to most often multiperitheciate, white pruinose
when young, dull black with age, strongly carbonaceous, with well-exposed perithecial
mounds.
Perithecia globose to obovoid, up to 1.2 mm diam x 1.8 mm high, seated on
a thick whitish to grey brown tisue extending upwards between the perithecia.
Ostioles coarsely papillate.
Asci cylindrical, long-stipitate, with
apical apparatus amyloid, urn-shaped to
cuboid, 4-4.8 µm broad x 5-6 µm high (collections on Salix) to 5.5-6
µm broad x 6-6.8 µm high (collection on Populus).
Ascospores brown, ellipsoid to slightly ellipsoid-inequilateral, with broadly
rounded ends that are usually thickened and darker, frequently rectangular in
outline (collections on Salix),
17.5-23 x 7.5-10 µm (collections on Salix) to 22.5-30 x 8.11 µm (collection
on Populus), with germ slit conspicuous, straight to slightly oblique or sinuous,
spore-length, on the more convex side; epispore non dehiscent in
10% KOH, smooth. Anamorph in nature not observed.
Specimens examined: FRANCE: Ariège (09): Quérigut, le Pla, Usine
EDF du Rialet, 1200 m. elev., 27 Sept. 1995, FC-5254, on dead standing Salix
caprea; Rimont, Las Muros, 480 m. elev., 11 Mar. 1996, JF-96022, on broken
off branch of Populus tremula. Aude (11): Belcaire, 1000 m. elev., 23
Sept. 1995, JF-95006, leg. FC, on Salix sp. SWITZERLAND:
Davos, Zügenschlucht, 1300 m. elev., 04 Sept. 1982, FC-5254, leg. L. Petrini,
on Salix appendiculata.
Notes: as pointed out by previous authors quoted in the introduction,
ascospore size is variable, ranging in our specimens from 17.5 to 30 µm
long and from 7.5 to 11 µm broad, but these values fall into the range given
by these authors.
But unlike Rogers and Ju (1996) who describe ascospores of
E. mammata more or less rectangular versus ellipsoid more or less inequilateral
in E. callimorpha, we found both ascospore shapes in our specimens,
ascospores tending to be rectangular in all collections on Salix
and ellipsoid and larger in one collection on Populus.
This observation corroborates what is reported by
Mathiassen (1993).
Rogers and Ju (1996), quoting French et al. (1969),
reported that cross-inoculation
of isolates of E. mammata from Alnus, Populus and Salix showed
a certain degree of incompatibility that could be related to host specificity.
Nevertheless, they did not found enough morphological differences between these
populations and concluded to the homogeneity of this species.
Beside these commonly reported hosts,
Granmo et al. (1999) added Sorbus aucuparia as a
frequent host in northern Europe.
Unlike Rogers and Ju (1996), we failed to observe the typical conidia-bearing
pillars rupturing the bark, probably because we failed to find young enough
stromata associated with the anamorph. Entoleuca mammata develops in bark of
dying branches in the canopy and usually is old and in poor condition when the
branch is found on the ground. We also failed to observe the production of cankers
reported by Rogers and Ju (1996), maybe due to less virulent strains presents
in our regions.
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