E-Flora BC: Electronic Atlas of the Flora of British Columbia

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.

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).

Fruiting body:
"irregularly rounded, cushion-like stroma breaks through the bark and can remain isolated or fuse with others" to form surfaces of several centimeters square; the surface is "dotted with warts", the papilla-shaped openings (ostioles) of the perithecia; perithecia 0.04-0.05cm wide, black, evenly embedded in a single layer in the black, coal-like stroma, (Breitenbach), stromata applanate [flat], 1.8-7cm x 0.5-4cm x 0.06-0.1cm, outer dehiscing layer dark brown, 0.04-0.08cm thick, "mature surface blackish to shiny black", "carbonaceous immediately beneath surface and between perithecia", tissue under perithecia inconspicuous; perithecia 0.01-0.02cm across, 0.05-0.08cm high, "obovoid to tubular, laterally flattened", usually "several packed inside the same stromatal locule", 0.03-0.05cm in diameter, "and sharing a common ostiolar canal"; ostioles higher than stromatal surface, with openings coarsely papillate, (Rogers), stromata erumpent from bark, 2-5cm long and 0.1-0.15cm thick, nearly round to elliptic, flattened to convex, "very carbonous, black and shining"; surface studded with coarsely papillate ostioles, 2-3 per mm; perithecia "oblong, compressed when crowded, monostichous", 0.04-0.05cm wide and 0.05-0.1cm high, (Miller, J.H.)

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.)