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

Summary:
Ascobolus immersus is a common species on herbivore dung. It grows more or less immersed, with a yellow or greenish yellow disc, and is recognized by the very large spores with a thick glutinous envelope surrounding each spore.

It is found at least in BC, CO, and AZ, (Larsen). Collections were examined from OR, ON, PQ, AZ, CO, CT, HI, IA, MA, ME, NJ, NY, VA, Argentina, Bermuda, Brazil, Puerto Rico, Austria, Belgium, Czechoslovakia, Denmark, France, Finland, Germany, Iceland, Italy, Luxembourg, Netherlands, Poland, Switzerland, United Kingdom, India, Pakistan, Australia, and New Guinea, (Brummelen).

Upper surface:
subcylindric or hemispheric, immersed in dung up to the margin, disc up to 0.1cm across, flat or convex, disc "yellow or greenish, with only a few protruding asci", (Dennis), 0.05-0.1(0.15)cm across, 0.05-0.07cm high, at first immersed or partially immersed, then erumpent or superficial, spherical or pear-shaped, "at first closed, then irregularly opening near the top", without margin, disc flat or convex; disc yellow or greenish yellow, "with only a few ripe asci protruding far above the surface", these easily visible with a hand lens as black spike-like protuberances; smooth or covered with thin layer of downy colorless hyphae, more rarely somewhat furfuraceous, (Brummelen), not exceeding 0.1-0.2cm across, at first immersed or partly immersed, expanding and becoming subturbinate [somewhat top-shaped], spore-bearing upper surface flat or more often convex, similar in color to exterior, (Seaver)

Underside:
outer surface may be covered by a thin layer of appressed hyphae but there are no distinct hairs, (Dennis), yellowish brown or greenish brown or yellowish, "rarely with a reddish or purplish hue", (Brummelen), greenish yellow, becoming brownish (Seaver)

Microscopic:
spores mostly 50-75 x 25-40 microns, oblong-elliptic, "smooth or with one or very few longitudinal splits in the epispore, surrounded by a thick, colourless gelatinous envelope", violaceous then brown; asci 1-40 per fruitbody, up to 8-spored, up to 700 x 130 microns; paraphyses slender, up to 3 microns wide, colorless, embedded in yellow mucus, (Dennis), spores (35)58-71(81) x (24)28-36(40) microns, oblong-elliptic, more rarely cylindric or nearly round, rounded at ends, "smooth or with one or a few lines which occasionally anastomose", sometimes with a coarse or fine network of narrow lines, a thick gelatinous envelope surrounding each spore, spores at first colorless, then purple or violet, finally sometimes purplish brown, spores biseriate or irregularly disposed; asci 8-spored (but often with only a part of the spores developed), 1-40 per fruitbody, 490-720 x 100-130 microns, with short stem, rounded at top, walls amyloid; paraphyses filiform, 2-3 microns wide, simple or branched, septate, not enlarged at tip, colorless, embedded in abundant greenish yellow mucus, (Brummelen)