While liverworts are common and ubiquitous in Maine, most people are unaware of them. Liverwort identification resources that are applicable to the northeast are limited. You will find below the sparse resources I've found that are useful. In addition I've adapted several keys and checklists for the northeast. I frequently use multiple keys to get a definitive ID and thus I've posted adaptations of the keys that I use.
Taxonomy is in a state of flux due to technological innovations. Liverworts are no exception. I am only half-heartedly attempting to determine the 'correct' scientific names and add them to the keys. Referenced suggestions always welcome!
Key to Hornworts & Liverworts of New England - This key was adpated from Sargent & Lucas key below. It has been modified with permission to make it specific to the northeast. Like their other keys, it is perspective based.
Key to Leafy Liverworts of Eastern Canada - This key was adapted from Syllogeus 62 below. It includes nearly 60 species common in the northeast.
Annotated Checklist of Liverworts in the Northeast - This checklist was 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
How To Know the Liverworts - coming 2022?
Most Common New England Liverworts - A checklist from Lincoln of the most commonly encountered liverworts in New England. This is a nice list but if you spend any significant amount of time looking, you will encounter others. Discoveries await!
Liverworts by Habitat - coming 2022?
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 thin 162 page book is available from the New York Botanical Garden https://nybgshop.org/ for $45. I use this reference A LOT! Beggars can't be choosers so I'll say no more.
How to Know the Mosses and Liverworts 2nd Edition by Henry S. Conard & Paul L. Redfearn (1979) - This out of print reference is one I still use for liverworts. The keys and glossary are good. While this doesn't stack up well against modern field guides and the taxonomy is somewhat out of date, you will usually get an ID. Recommended. Used copies are typically inexpensive. An adaptation of the liverwort keys applicable to the northeast is in progress.
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 has passed into 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.
Flore des Bryophytes du Quebec-Labrador by Jean Faubert (2012) - A three volume set written in French. I have seen this and it is very nice - however my French hasn't been used in more decades than I care to name. Volume 1 covers the liverworts and hornworts. $310 Canadian for the 3 volume set. Please Santa!?
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.
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 only is above.
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.
Bryophyte Flora of North America - Hepaticae (Liverworts) - This work covers the entire flora of North America. This link is to the very much in progress FNA Volume 29: Hepaticae (Liverworts). 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.
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.
Suggestions, errors or a key you wish to have posted? Email info@DigitalNaturalist.info.
last update 2024-Apr-24