Summary:
Features include cup-shaped to saucer-shaped fruitbodies that are yellowish green then brownish to blackish, dotted with protruding asci, the exterior somewhat lighter in color and finely mealy or scaly, margin that is weakly scurfy-notched, absent stem, growth on burned ground or charcoal, and microscopic characters including warted spores that are colorless to purplish.

Microscopic:
spores 17.5-25(27.5) x (11.5)13-14.5 microns (including pigment), elliptic, with pointed ends when immature and with truncate ends when mature (with pigment), rarely swollen, at first colorless, then dark violet, finally dark purplish brown, "ornamented with irregular or rounded, isolated warts varying considerably in size", "pigment in a very thick layer, at the sides 1.5-2.7 microns thick, at the ends 2.4-3.1 microns thick", spores uniseriate in ascus, finally more or less biseriate; asci 8-spored, 190-270 x 22-26 microns, cylindric-clavate, narrowing downwards, rounded at top, only when young the wall pale blue in Melzer''s reagent; paraphyses about 2 microns thick, cylindric, septate, occasionally branched, not or scarcely thickened in upper part, up to 3.5 microns thick at tip, embedded in yellowish green mucus, (Brummelen), 22-23 x 13-14 microns (not including warts), broadly elliptic, warty, warts projecting up to 1 micron, (thickened warts at poles not seen), violet-brown when mature; asci 8-spored, 150-230 x 13-22 microns, amyloid; paraphyses filiform [thread-like], septate, forked, (Breitenbach)

Notes:
Ascobolus carbonarius is found at least in BC, OR, CA, and AB, (Larsen). Collections were examined from OR, MB, PQ, CT, IA, IN, MI, ME, NC, NY, OH, PA, TN, VA, WI, WV, Costa Rica, Austria, Belgium, Czechoslovakia, Finland, France, Germany, Italy, Netherlands, Poland, Sweden, Switzerland, United Kingdom, and Uganda, (Brummelen).

Synonyms and Alternate Names:
Peniophora carnosa Burt
Peniophora firma Burt