Several other black earth tongue species are quite similar in external appearance, and many can be reliably distinguished only by examining differences in microscopic characteristics, such as spores, asci, and paraphyses.

[12] In 2015, Hustad and Andrew Miller published an emended description of G. glutinosum with a narrower range of spore dimensions, suggesting that material collected in Australia and New Zealand represent unique species, which they referred to G. australasicum and G. exiguum.

Hustad and Miller noted their new spore size range for G. glutinosum were more closely aligned with those given by Durand in his measurements of Persoon's type specimen.

The club-shaped fruitbodies, which have a distinct blackish head and a more lightly colored stipe (dark brown), grow to heights ranging from 1.5 to 5 cm (0.6 to 2.0 in).

[6] Although black earth tongue species are generally not worth eating,[14] Charles McIlvaine opined in his 1902 work One Thousand American Fungi that, if stewed, G. glutinosum is "delicious.

[17] The Australasian species Glutinoglossum methvenii is distinguished from G. glutinosum by its short, stout ascospores (mostly measuring 70–80 by 5–6 μm) and the presence of curved to hooked paraphyses tips.

[8] A widely distributed species, Glutinoglossum glutinosum has been recorded from northern Africa (Macaronesia[22]), Asia (Bhutan,[23] China, India,[23] Japan,[24] and the Philippines[25]) and Europe.

[26] In Bulgaria, where it is considered critically endangered, threats to G. glutinosum include "habitat changes as result of agriculture activities (crops, livestock), atmospheric and land pollution, drought, global warming.

"[27] In a preliminary Regional Red List of Dutch macrofungi, G. glutinosum was considered threatened, and it was noted that before 1970, the fungus was "rather common", compared to "rather rare" after that year.

[30] Although G. glutinosum was previously thought to have occurred in Australia and New Zealand,[12][31] later examination and genetic analysis of collections from these locations showed the material to belong to what have since been described as the new species G. australasicum or G. exiguum.