I frequently use multiple keys and thus I've posted adaptations of the keys that I frequently use.
Taxonomy is in a state of flux. Referenced nomenclature changes always welcome!
Annotated Checklist of Liverworts in the Northeast - This checklist was originally derived from the BFNA treatments that were posted as of February 2022 and then the nomenclature updated to match Stotler and Crandall-Stotler 2017 listed below
Key to Leafy Liverworts of Eastern Canada from Syllogeus 62 - Key adapted from Syllogeus 62 below includes nearly 60 species common in the northeast.
Key to Liverworts from How to Know the Mosses and Liverworts - Key was adapted from How to Know the Mosses and Liverworts below and includes nearly all the genera in North America.
Key from Enthusiasts Guide to the Liverworts and Hornworts - Key from Enthusiasts Guide to the Liverworts and Hornworts below. It includes most species in the Northeast.
Perspective Based Key to Hornworts & Liverworts of New England - This key was adapted from the Perspective Oriented Guide... below. It has been modified with permission to make it specific to the northeast. Like their other keys, it is perspective based.
Guide to Relative Size of Liverworts - A list of New England liverworts grouped by their relative sizes. Adapted from An Enthusiasts Guide to the Liverworts and Hornworts of Ontario
Liverwort Habitats - A list the liverworts and hornworts from the New England and the Maritime Provinces by their most common substrate or habitat
Most Common New England Liverworts - A checklist adapted from Lincoln of the most commonly encountered liverworts in New England. If you spend any significant amount of time looking, you will encounter others.
Bryophyte Flora of North America - Liverworts & Hornworts - This link is to the very much in progress FNA Volume 29: Liverworts and Hornworts. You will find links to keys, species descriptions, and illustrations for the parts that are complete. While incomplete, what is there is pretty much the only modern liverwort resource. Links are grouped by Family and Genus.
Perspective Oriented Guide for the Identification of North American Bryophyte Genera. - This outstanding set of documents last updated in 2012 is available online or as printable PDFs and Microsoft Word documents. I highly recommend this text only key. I often find it far faster and easier to use than any of the other keys. Scroll down for Liverworts & Hornworts. Make sure you read and understand the Introduction and Appendix A - Quick Start Instructions as this is not a typical dichotomous key. My adaptation for New England is above.
Syllogeus 62 - Illustrated Guide to Some Common Liverworts, Hornworts and Mosses of Eastern Canada by Robert R. Ireland & Gilda Bellolio-Trucco (1987) - This excellent work is now public domain. It is available at www.biodiversitylibrary.org and from this website HERE as a 7.5Mb download. The adapted liverwort keys are available above.
Consortium of Bryophyte Herbaria - The Consortium of Bryophyte Herbaria (bryophyteportal.org)aims to unite bryophyte specimen records from around the world and serve as a gateway to distribute these resources to the public. It has tools to work with a variety of data, including specimen records, field observations, dynamic and static checklists, images, interactive keys, and a taxonomic thesaurus.
British Bryological Society Species Finder - The BBS has a great website and awesome field guide to bryophytes. Scroll down a bit to use the liverwort filter. While the validity of names across the Atlantic is sometimes questionable, the fantastic pages of liverworts from the field guide are worth a look. Moss pages are less useful on our side of the pond.
A Synopsis of the Liverwort Flora of North America North of Mexico by Raymond E. Stotler and Barbara Crandall-Stotler, Annals of the Missouri Botanical Garden 102(4), 574-709, (29 December 2017). doi.org/10.3417/2016027 A comprehensive list with annotations on the confusing nomenclature and taxonomy of liverworts. $20 to buy the PDF and access to the article web page.
World checklist of hornworts and liverworts (2016) - The open source publication that lists all accepted taxa - 7486 species in 398 genera representing 92 families for liverworts and hornworts world wide. One can download the 5Mb PDF or a few other formats.
Missouri Department of Conservation Discover Nature Field Guide - A nice little primer on liverworts. Genera mentioned all occur in the northeast.
What is a liverwort? from the Australian National Herbarium is also a nice primer though many of the genera mentioned do not occur in the northeast.
Mosses, Liverworts, and Hornworts : A Field Guide to the Common Bryophytes of the Northeast by Ralph Pope (2016) - Despite my laments elsewhere on this page, this book does an excellent job of covering the liverworts likely to be encountered by all but the most persistent. An verdant oasis in an otherwise barren field - and it covers mosses well too!
Liverworts of New England by Mary S. G. Lincoln (2008) - If you want something more comprehensive than above, you have a single option. This 162 page book was available from the New York Botanical Garden https://nybgshop.org/ for $45. I use this reference A LOT, but as of June 2025 it appears to be out of print.
An Enthusiasts Guide to the Liverworts and Hornworts of Ontario by Linda M. Ley and Joan M. Crow (1999). This out of print reference is worth looking for. Only 3 or 4 species are not found in New England. Naturally the taxonomy is outdated but otherwise I highly recommend this one.
How to Know the Mosses and Liverworts 2nd Edition by Henry S. Conard & Paul L. Redfearn (1979) - A serviceable out of print reference. The keys and glossary are good. While this doesn't stack up well against modern field guides and the taxonomy is dated, you will usually get an ID for common species. Used copies are typically inexpensive. My adapted version of the liverwort only keys is above
The Liverworts Flora of the British Isles by Jean Paton (1999) - A reference for the serious that is worth seeking. www.summerfieldbooks.com in the UK has availablity in paperback.
A Supplement to The Liverwort Flora of the British Isles by Jean Paton 2022 - A 26 page hardcover update to the above.
Flore des Bryophytes du Quebec-Labrador by Jean Faubert (2012) - A three volume set written in French. Though my French hasn't been used in more decades than I care to name this is still a very usable reference. Volume 1 covers the liverworts and hornworts. $310 Canadian for the 3 volume set.
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last update 2025-Jul-04