Nemania carbonacea Pouzar.
This taxon was described in detail by Pouzar (1985 a). According to this
author, it is related to N. diffusa [as N. bipapillata (Berk.
& M. A. Curtis) Pouzar] in having similar dark brown ascospores with
a conspicuous germ slit spore-length. They differ in that stromata of N.
carbonacea have conspicuous perithecial mounds and become black when mature,
while in N. diffusa perithecial mounds are inconspicuous and mature stromata
keep a brown tinge. Moreover, Ju & Rogers (2002) pointed out that stromata
of N. carbonacea have white soft tissue between perithecia while
those of N. diffusa are more carbonaceous.
According to Pouzar (1985 a), this species has been recorded on various hosts
(Acer campestre, Carpinus betulus, Fagus sylvatica, Quercus petraea,
Populus nigra and Tilia cordata) in Czech Republic, where it does not seem to be uncommon.
We so far failed to find it in France, while it has been recently reported from
Denmark and Sweden on Betula and Corylus by Granmo et al.