Biscogniauxia cinereolilacina (J. H. Miller) Pouzar.
Stromata applanate, up to 6 cm long x
2 cm broad x 0.8 mm thick; surface dull purplish brown when young to grey
when mature, weakly carbonaceous, with a brown dehiscing outer layer when
young; basal tissue under the perithecia absent.
Perithecia obovoid, 0.3
mm diam x 0.5 mm high.
Ostioles black, papillate.
with a weakly amyloid discoid apical ring.
Ascospores light brown to
brown, ellipsoid nearly equilateral, 12-14 x 5.5-7 µm, with a straight germ
slit spore-length on both sides.
Specimen examined: FRANCE: Hautes Pyrénées, Luz Saint Sauveur, 27
Sept. 1987, FC-5250, on Tilia.
Notes: Biscogniauxia cinereolilacina is peculiar in two respects
which are diagnostic: its stromatal surface is distinctly purplish to grey
and its ascospores have a circular germ slit. All other species of Biscogniauxia
known from Europe have a blackish stromatal surface. A germ slit on both
sides of ascospores is also present in B. querna and B. repanda
but these species differ in having raised stromatal margins giving a cupulate
habit to the stroma; in addition, their ascospores are darker and broadly
ellipsoid, larger in B. querna, smaller in B. repanda.
This rarely recorded species is known from Europe (Bulgaria, Czech Republic,
France, Hungary, Norway, Sweden) (Pouzar, 1986), (Granmo et al., 1989),
(Granmo and Petrini, 1996), and North America (Canada, U. S. A.) (Ju et al.,
1998), and seems restricted to Tilia sp.