Usually with perithecial fungi you can either make out the individual, hemispherical perithecia (even if they are only a millimetre or so in diameter) or see a mass of such perithecia growing densely packed so as to give a cobblestone-like look (each 'cobble' being a single perithecium). Sure, you may sometimes see a fuzzy growth of the asexual sporing stage spreading over the perithecia, but usually you can still get an idea of the underlying perithecia.