Tapinella atrotomentosa was originally described as Agaricus atrotomentosus by German naturalist August Batsch in his 1783 work Elenchus Fungorum,[3] and given its current name by Josef Šutara in 1992.

[1][9] The variety bambusinus was described from Trinidad in 1951 by British mycologists Richard Eric Defoe Baker and William Thomas Dale.

[14] The fruit body is squat mushroom with a cap up to 28 cm (11 in) across, sepia- or walnut brown in colour with a rolled rim and depressed centre.

[24] Linus Zeitlmayr reports that young mushrooms are edible, but warns than older ones have a foul bitter or inky flavour and are possibly poisonous.

[25] Tapinella atrotomentosa has a wound-activated defence mechanism whereby injured fruit bodies convert chemicals known as leucomentins into atromentin, butenolide, and the feeding deterrent osmundalactone.

[30] Several phytoecdysteroids (compounds related to the insect moulting hormone ecdysteroid) have been identified from the fungus, including paxillosterone, 20,22-p-hydroxybenzylidene acetal, atrotosterones A, B, and C, and 25-hydroxyatrotosterones A and B.