Ecology: Montane forest; on branches of trees. Elevation: 1470-2600 m. Distribution: Endemic to the tropical Andes (Bolivia).

Acidodontium lonchotrachylon is distinguished by the lustrous, medium sized to rather robust plants to 1.7 cm, broadly oblong to subelliptical leaves to 3.6 mm long, somewhat undulate to twisted and appressed when dry, spreading when wet, abruptly acuminate apex ending in a flexuous, often denticulate, capillary point, indistinct, elongate cell border, subpercurrent costa, 2 rows of cells forming a distinct border below, above indistinct with 1 elongate cell, setae to 20 mm, clavate capsule to 3 mm (neck about equal the length of the urn), broad hemispherical, non-apiculate operculum. The type of Bryum lonchotrachylon Müll. Hal., as well as the Bryum brachypodium Müll. Hal. (synonym), were both collected by Germain in 1889 from Choquecamata.

Specimens: BOLIVIA. Cochabamba: Germain s.n. (S); Santa Cruz: Herzog 4319 (L).