Macoun's shining moss was a large bryophyte with long greenish-brown tufts.

It lived near the base of tree trunks of various species of elm and cedar that grew in swampy areas.

Most recent publications accept the current classification of Macoun's shining moss.

[1] The common name honours John Macoun (1831–1920), who was an Irish-born Canadian naturalist.

[2] The area where the samples were found was clear-cut for economic purposes between 1864 and 1892, implying that the species became extinct due to habitat loss during that time.