Although members of
Coenogonium are relatively easy to identify given its unique characteristics, identifying to species is more difficult due to the slight differences between them. The genus is characterized by (rarely ), yellow to orange or brown
apothecia with a excipulum, partially
amyloid hymenium (I+ blue then quickly sordid green then red-brown), thin-walled unitunicate
asci, and 1-
septate or rarely non-septate
ascospores. The
photobiont component of
Coenogonium is a
green alga from the family
Trentepohliaceae. The structure of the
Coenogonium thallus is largely determined by the algal partner. Similar genera include
Malcolmiella, which differs mainly by having
amyloid asci with a thickened and non-septate, usually longer and broader ascospores with an ornamented ;
Absconditella, which has a photobiont and non-amyloid asci; and
Cryptodiscus, which has
Gloeocystis as photobiont, amyloid asci with a thickened apex and non-septate
paraphyses. ==Research==