Below is a working checklist of Mount Desert Island's hornworts. This list and nomenclature is based on a very old (1924) article in Rhodora, the journal of the New England Botanical Club. Therefore, there is likely much updating of the taxonomy necessary.
Please send corrections and updates to info@vfthomas.com. Photographs are welcome. Thank you.
| Family | Genus | Specific Epithet | authority | common name | Source (full citation given after this table) |
| Anthocerotaceae | Anthoceros | laevis | L. | ? | Bar Harbor: Lorenz (1924, p. 13., "Cadillac Cliff at Sea Cave") Mount Desert: Lorenz (1924, p. 13., "Seal Harbor", "roadside near Prettymarsh") town?: Lorenz (1924, p. 13., "Great Pond") |
| Anthocerotaceae | Notothylas | orbicularis | (Schwein.) Sull. | ? | Bar Harbor: Lorenz (1924, p. 13., "roadside between Town Hill and Indian Point") |