Summary:
Features include 1) fruiting on hardwood, especially oak, usually following fire or drought injury, 2) irregularly rounded, cushion-like fruitbodies that break through the bark and may fuse with others to form a surface several centimeters square, the surface dotted with the papilla-shaped openings of the perithecia, 3) spores that are narrowly elliptic, smooth, and dark brown, with the germ split the full length of the spore, 4) asci that are 8-spored with the apical ring turning blue in Melzer''s reagent, and 5) inconspicuous paraphyses.

Microscopic:
SPORES 17-24 x 7-10 microns, narrowly elliptic, smooth, dark brown, with 1 droplet and indistinct germ slit, uniseriate in ascus; ASCUS 8-spored, 150-180 x 7-10 microns; PARAPHYSES cylindric, indistinctly visible, (Breitenbach), SPORES 15.5-21 x (6.5)7-10 microns, elliptic, "nearly equilateral, with narrowly to broadly rounded ends", smooth, brown to dark brown, unicellular, with straight germ slit spore-length; ASCUS 160-185 x 9-12.5 microns, the spore-bearing part 120-150 microns long, stem 20-35 microns long, with apical ring turning blue in Melzer''s reagent, discoid, 2-3 microns high and 4-5 microns wide, (Rogers), SPORES 16-23 x 6-10 microns, (var. microspora 12-15.2 x 5-8 microns, var. macrospora 22-34 x 13-17 microns), "oblong-elliptic, usually with obtuse ends, dark brown"; ASCUS 120-185 x 8-11 microns (80-100 x 7-9 for var. microspora), cylindric, short-stemmed; PARAPHYSES, straight bands, numerous, (Miller, J.H.)

Notes:
Biscogniauxia mediterranea is found in "All of United States", Canada, France, Germany, Portugal, Italy, China, Africa, and Australia; collections of var. microspora were examined from BC, WA, CA, Africa, China, Philippines, New Zealand, and Samoa, and a collection of var. macrospora was examined from Venezuela, (Miller, J.H.). Collections were examined from OR, AL, CA, IN, NC, ND, NJ, NY, OH, PA, VA, WI, Mexico, Brazil, Austria, France, Germany, Italy, Portugal, Ukraine, Georgia, Russia, Mauritania, and Nigeria, (Rogers).