Mycoporum antecellens  

Thallus whitish, greenish white or pale brown, not lichenized (though frequently accompanied by free-living algae).
Anamorph: conidiomata pycnidia, ca 100 μm diam., sometimes numerous, black. Conidia 4-6 × ca 0.8 μm, bacilliform.
Teleomorph: stromata absent. Ascomata perithecia, 200-400 µm dia. and 200-300 µm high, not compound, circular to elliptical in surface view. Involucrellum yellowish brown in K. Interascal cells of pseudoparaphyses 1.5-2.5 μm diam., persistent, much branched, cells 7-16 μm long. Asci 65-105 × (20-) 25-35 (-40) μm, obpyriform, thick-walled and fissitunicate, 8-spored. Ascospores 27-40 × 8-13 μm, 1- (to 3-) septate, usually strongly constricted at the median to supramedian septum, the lower cell sometimes slightly constricted in the mid portion, the apices obtuse to acute, at first hyaline but often becoming brownish and finely warted, thick-walled, smooth, without a distinct epispore, gelatinous sheath or appendages.
Chemistry: lichen products not detected by TLC.