Bryolog 25 (25 August 2021)


  • Virtual Workshop, “Introduction to Bryophytes,” Saturday 12 March 2022

On 12 March 2022 (9:00–12:00 and 1:00–4:00), Brent Mishler will be leading a virtual workshop, “Introduction to Bryophytes,” hosted by the Jepson Herbarium. This is a virtual reincarnation of the famous in-person Jepson workshop offered every other year since 1994, and like its predecessors will provide participants with the opportunity to learn more about the evolution, ecology, and systematics of mosses, liverworts, and hornworts. It will also cover introductory topics on how to identify them. Given the virtual format, we will not be able to have the hands-on microscope sessions and field trip we have traditionally included, but we will cover some useful techniques through demonstrations.

The timing of this workshop is perfect for SO BE FREE 26, which will be held 25–28 March 2022 in the Mojave desert at Zzyzx (near Baker). Hands-on microscope sessions and field trips will be held there. So those who can attend both the workshop and SO BE FREE will get a very complete introduction to the world of bryology, although each freestanding event is valuable in itself.

This is just a save-the-date announcement. Registration details will be will be posted in early December at

  • SO BE FREE 26 Coming up 25–28 March 2022 in the Mojave desert 

Save the Date: The upcoming 2022 So Be Free will be held at the CSU Desert Studies Center in Zzyzx ( Located at Soda Springs, perched at the edge of Soda Dry Lake, the Desert Studies Center is a 1200-acre field station located within the Mojave National Preserve. Habitats in the immediate vicinity of the Desert Studies Center include seeps and springs, ponds, seasonal vernal pools, salt marshes, alluvial fans, and dunes. The Desert Studies Center also provides access to interesting habitats within the Mojave National Preserve and nearby areas, including desert washes that support well established soil crust communities dominated by desert mosses. Be on the lookout for registration information posted on the chapter webpage, coming soon!

  • A special bryophyte issue of Madroño, A West American Journal of Botany, published by the California Botanical Society (CBS), will appear later this year as Volume 68, Issue 3, 2021. Read about its contents and how to order at a pre-publication discount HERE…

Quarterly Report

  • Stacey Anderson reports on the first-ever moss walk in Larimer County, Colorado, HERE…

Timeless Bits

  • Tribute to Judith Harpel, 1950-2021 MORE…
  • Daunting Didymodon: a difficult genus being realigned (again), by James Shevock MORE…
  • Clevea hyalina in Southern California by Chris Wagner MORE…
  • Freezing liverworts for oil body data by David Wagner MORE…
  • Instructional image naming parts of the peristome in Rhytidiadelphus loreus by David Wagner MORE…
  • Ralf Reski’s moss evolution video

Pre-announcement: Madroño bryophyte issue

A special bryophyte issue of Madroño, A West American Journal of Botany, published by the California Botanical Society (CBS), will appear later this year as Volume 68, Issue 3, 2021. This will be the fifth special bryophyte issue published by the CBS.

This special issue entitled Contributions toward a Bryoflora of California V and the West (estimated to be nearly 200 pages) will include six bryophyte floristic works. They are:

A bryophyte inventory of Mount Diablo, Contra Costa County, California by David Hutton, John C. Game, Kiamara F. Ludwig, Javier Jauregui Lazo and Benito C. Tan†

A preliminary specimen-based catalogue of the moss species found in Napa County, California by Stephen P. Rae

A preliminary checklist of the bryophytes of San Luis Obispo County, California by Benjamin E. Carter

A flora of the mosses of the Cascade-Siskiyou National Monument in Oregon and California by Jason R. Brooks

Bryoflora of the Shoshone National Forest, Wyoming. Part 1. A catalogue of mosses and liverworts of the Beartooth Plateau area by Yelena Kosovitch-Anderson

Bryoflora of the Russian Wilderness and adjacent slopes of the Salmon Mountains, Klamath National Forest, Siskiyou County, California by James R. Shevock, David R. Toren and David H. Wagner

At this time a special pre-publication price is available to order at for only $20. Payment can be easily handled by paypal. This issue will be $25 once published, so order your copy today and save 20%.

The previous four special bryophyte issues are also still available at the CBS website for purchase. They are:

Contributions toward a Bryoflora of California I. A specimen-based catalogue of species by Daniel H. Norris & James R. Shevock. Madroño 51(1): 1–131, 2004.

Contributions toward a Bryoflora of California II. A key to the mosses by Daniel H. Norris & James R. Shevock. Madroño 51(2): 133–269, 2004.

Contributions toward a Bryoflora of California III. Keys and annotated species catalogue for liverworts and hornworts by William T. Doyle & Raymond F. Stotler. Madroño 53(2): 89–197, 2006.

Contributions toward a Bryoflora of California IV. A checklist of the bryophytes of the Channel Islands by Benjamin E. Carter, A catalogue of the mosses of the Plumas National Forest by Colin P. Dillingham, and A moss flora of Lake County, California by David R. Toren. Madroño 62(4): 185–268, 2015.

Colorado Moss Walk

—Stacey Anderson

The first moss walk in Larimer County, Colorado, was held June 1, 2021, at Gateway Natural Area in the Poudre River Canyon west of the city of Fort Collins and was sponsored by the Northern Chapter of the Colorado Native Plant Society.

Gateway is a historical water filtration plant for Fort Collins at the confluence of the Poudre River and its north fork. There are steep hills with rocky, granitic outcroppings with Ponderosa Pine and Douglas Fir growing on them. The filtration plant was built in the early 1900s and operated as the main water source for Fort Collins until the late 1970s when it was closed to the public. In 2002, after renovations by the community, it was reopened under management of the Fort Collins Parks and became a natural area in 2006.

Because of the canyon terrain, shady habitat, and rivers, this area has an abundance of typical montane, forest floor mosses. Eight very enthusiastic people, through the Colorado Native Plant Society, joined leader Stacey Anderson (a three-time attendee to SoBeFree) to learn about bryophyte basics, why moss matters, and eight easy to recognize species common to Gateway Natural Area, along with those longstanding favorites Ceratodon purpureus and Bryum argenteum. The mosses found included the following: Hypnum revolutumAbietinella abietinaRhytidium rugosumHedwigia ciliataSyntrichia ruralisOrthotrichum halliiGrimmia sp., and Polytrichum piliferum.

The consensus at the end of the walk was Colorado mosses are fascinating and WHO KNEW? There was great interest in continuing with more moss walks and possibly workshops in the future. The lonely mossers of Colorado are finding others to share this tiny-huge world of bryophytes with. Thanks to Dr. Brent Mishler and Dr. David Wagner for their contributions of teaching materials and modeling how to conduct a moss walk, and to Chuck Anderson for his super help. And to so many others who introduce and support beginners in this fabulous journey to see and understand the bryophytes out there.

Stacy teachingpeople looking through hand lensesPeople taking notes

people collectingpeople in the distance walking down a trail, in peace

Tribute to Judith A. Harpel, 1950–2021

—Brent D. Mishler, David R. Toren, René J. Belland, Cynthia M. Galloway, John R. Spence, and James R. Shevock

Judy Harpel, looking anticipatory

Judy Harpel was a perceptive field bryologist, an active collaborator, and a leader in bryophyte conservation efforts. She will be greatly missed by the bryological community. She began working with bryophytes in the mid 1970s as a masters student at California State Polytechnic University, Pomona with Marion Harthill, when two of us (BDM and CMG) were also masters students in the same lab. Professor Harthill had all his students working on bryological floristic projects across southern California, and it was a lively bunch learning together, with Judy serving as the social nucleus. Judy did an outstanding study for her masters thesis on the San Jacinto Mountains, a relatively unexplored region where she found many important range extensions (Harpel 1980).

Cyndy Galloway relates: “I first met Judy when I was an undergraduate student working in the herbarium at California Poly Pomona. The minute Judy stepped into the herbarium I knew I had a mentor and friend. She never hesitated to stop what she was doing to help verify my determinations. One summer, three of us, Judy, myself and an undergraduate, Kurt Waln, traveled by train from Southern California to attend the summer class given by Dr. Howard Crum at the University of Michigan field station at Douglas Lake. Judy put all of her effort into the bryology course, and Dr. Crum was always amazed that any time day or night when he came into the lab, Judy would be sitting there identifying mosses. She was determined to learn everything possible during the summer we were there. When we graduated Judy continued to confirm mosses for me from my Southern California collections. I doubt I will have a better friend and colleague as I had in Judy these last 45 years.”

Judy went on to make major contributions in floristics, biogeography, and conservation of bryophytes. She worked with the US Forest Service in Washington State as a Regional Interagency Bryologist. She served as the Forest Service cryptogamic specialist for the Northwest Forest Plan (within the range of the Northern spotted owl) in Washington, Oregon, and Northern California, where bryophytes and lichens dependent on old-growth forest were surveyed and managed. This was the first time bryophytes were considered in federal land management activities under the National Environmental Policy Act.

During her Forest Service career, she conducted bryophyte workshops and survey techniques on 21 different national forests as well as several Bureau of Land Management districts. She was especially interested in the conservation of bryophytes and was part of the bryophyte working group that got bryophytes added into the CNPS Inventory of Rare and Endangered Plants.

While working and raising a family she also studied with Wilfred Schofield at the University of British Columbia for her PhD, again carrying out a fascinating floristic study, this time of the San Juan Islands (Harpel 1997). She was very active in western North American bryophyte circles, sharing collections, helping people with identifications, and collaborating in fieldwork. She was a frequent participant in SO BE FREE meetings, including serving as primary organizer for the 2008 event.

David Toren relates that: “In the twenty-plus years I knew Judy, I always enjoyed her company in the field and appreciated her hospitality in her home where we spent countless hours in her herbarium during my many visits. She was always eager to show me bryophytes I had previously never seen in the field. One of the most memorable of these moments happened on a coastal beach in Washington state where she knew of a population of Schistidium maritimum. It was growing on the vertical side of a sea stack at least twenty-five feet above our heads. Judy quickly fastened together two long pieces of driftwood and handed this contraption to me. She pointed to the large colony, stood back, and screamed “Poke! Poke! POKE!” I yelled back “I am poking!” I finally dislodged the plants and they plummeted to the beach but not before I was showered with the fragments.”

John Spence remembers Judy’s enthusiasm for all things bryological: “We had many interesting conversations about mosses at SO BE FREEs, and she taught me the taxonomy and ecology of Claopodium, one of her favorite groups. She was always friendly and helpful, especially in responding to my numerous emails regarding collections from the Aleutian Islands.” Judy was an important and friendly liaison for the upcoming Moss Flora of the Aleutian Islands in general, doing often tedious work keeping track of thousands of collections sent out to various workers on the project.

Judy’s personal collections, which number around 50,000, span several western States, primarily Washington, Oregon, California, Idaho, Alaska, and the Yellowstone region. Her collecting expeditions also were conducted in several Canadian provinces. In the summer of 2001, she was a participant in the International Sakhalin Island Project to conduct biotic surveys. Judy’s personal herbarium will become part of the California Academy of Sciences herbarium in the near future.

Judy was a member of the Mosses and Lichens Species Specialist Subcommittee, which forms part of the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). She was a member of the subcommittee for about 20 years. The subcommittee assesses the risk of endangerment or extirpation across Canada. Judy’s extensive experience with bryophytes in the Pacific Northwest was invaluable to the subcommittee’s work since this region is a hotspot for rare and endangered bryophytes. Her extensive field experience in Oregon and Washington, as well as her experience in southwestern B.C., was unique on the subcommittee. Judy brought first-hand knowledge and insight to the table. Her collegiality and generous sharing of knowledge were an important contribution to the subcommittee work and the large gap that she leaves will be difficult to fill.

Judy Harpel, sitting

Publications of Judith A. Harpel

Harpel, J. A. 1980. A preliminary floristic study of the mosses in the San Jacinto Mountains: a Masters thesis presented to the faculty of California State Polytechnic University, Pomona, CA.

Harpel, J.S. 1980. Orthotrichum pumilum new to California. The Bryologist 83 (2): 20.

Harpel, J.S. 1982. Rods, bundles and stitches: basket materials. Riverside Museum Associates Report 8 (2).

Harpel, J.S. 1994. A preliminary report on the phytogeography and ecology of the mosses within the San Juan Islands, Washington. Northwest Science 68 (2): 128. Abstract.

Harpel, J.A. 1997. The phytogeography and ecology of the mosses within the San Juan Islands, Washington State, Ph.D. dissertation, University of British Columbia.

Harpel, J.S. 1997. Moss list for the Washington Department of Natural Resources. In: Endangered, Threatened & Sensitive Vascular Plants of Washington with Working Lists of Rare Non-Vascular Species. Olympia, WA. 106 pages.

Christy, J.A. and Judith S. Harpel. 1997. Rare Bryophytes of the Interior Columbia River Basin and Northern Great Basin, U.S.A. Journal of the Hattori Botanical Laboratory 82: 61-75.

Harpel, J.S. 2000. Noteworthy Collections, Jaffueliobryum raui, new to California. Madroño. 46: 215.

Harpel, J.S. 2001. Phytogeographic patterns of rare mosses in Washington State. In Conservation of Washington’s Rare Plants and Ecosystems. Eds. S.H. Reichard, P.W. Dunwiddie, J.G. Gamon, A.R. Kruckeberg, and D.L. Salstrom. Washington Native Plant Society, Seattle. 224 pages.

Harpel, J.S. 2006. A new combination in Tetraphis (Bryophyta: Tetraphidaceae). Sida, Contributions to Botany 22: 549–554.

Harpel, J.S. 2007. Tetraphidaceae Schimper. In Flora of North America. Eds. Flora of North America Editorial Committee (ed.). 27: 111, 116.

Harpel, J.S. 2010. A history of bryology in the San Juan Islands, Washington State, USA. Canadian Journal of Botany 88: 329–335.

Harpel, J.S. 2011. Bryophyte Fact Sheets, Field guide to Washington’s rare plants. Washington State Department of Natural Resources. Olympia, WA.

Harpel, J.S. 2014. Claopodium (Lesquereux & James) Renauld & Cardot. In Flora of North America. Eds. Flora of North America Editorial Committee (ed.). 28: 342.

Harpel, J.S. 2014. Iwatsukiella W. R. Buck & H. A. Crum. In Flora of North America. Eds. Flora of North America Editorial Committee (ed.). 28: 367.

Exeter, R.L., Harpel, J.A. & Wagner, D.H. 2016. Rare Bryophytes of Oregon. Salem District, Bureau of Land Management, Salem, OR 97306. 378 pp.

Daunting Didymodon: a difficult genus being realigned (again)

—James R. Shevock, California Academy of Sciences

Anyone working on Pottiaceae in western North America soon has to come to terms with naming Didymodon collections! Why have members of this genus been difficult to circumscribe and identify?

First off, as recently envisioned, Didymodon is among the largest genera within the Pottiaceae, with about 122 species viewed as worthy of recognition. It is useful to take a historical view of how this came to be. When Hedwig produced his magnum opus, Species Muscorum Frondosorum in 1801, he established the genera Barbula and Didymodon. However, while Barbula had many species, Hedwig listed Didymodon with only a single species. So what happened? Well, Barbula was basically a dumping ground for many pottiads. A quick look at the number of species originally described as a Barbula in Tropicos reveals more than 1900 names with dozens of sections and subsections. Today, Barbula is viewed as a genus of about 170 species (Crosby et al. 2000). In the 1800s, other bryologists began to review Barbula, and slowly various taxa were pulled out of it and either moved to other existing genera or to newly created genera. But with so many taxonomic hypotheses based solely on morphology, many of these new name placements received little use or wide acceptance among bryologists at that time. Schimper, in 1876, erected the genus Geheebia from a section of Barbula. Cardot, in 1909, likewise elevated sections of Barbula to generic status when he established the genera Husnotiella and Trichostomopis. Some of these genera appeared in various floras. Here in California a few Didymodon were reported as Trichostomopsis australasiae and Husnotiella revolutus while others remained in Barbula (Koch 1950).

But Didymodon as we have known it really took shape with the publication Genera of the Pottiaceae: Mosses of Harsh Environments (Zander 1993). In this work, Zander made 19 new name combinations in Didymodon. He placed some of the earlier generic names back within Didymodon, and did not recognize the genera GeheebiaTrichostomopsis or Husnotiella. But the story does not end there. Zander realized that Didymodon was heterogeneous. Later, Zander (2013, 2019) took a more splitter’s view of Didymodon. He created the genera VinealobryumAithobryum and Exobryum and recognized Geheebia. However, few bryologists followed suit.

And now we come to the multilocus phylogenetic study of Jiménez et al. (2021). This is indeed a monumental study. Even with these data, the taxonomic placements proposed will remain somewhat controversial. The Jiménez study concluded that Didymodon, in the broad sense, is comprised of eight well-supported monophyletic clades that can also be distinguished by morphological attributes. A key to the eight genera recognized appears in Jiménez et al. (2021). Several of these genera are elevated from sections within Didymodon. This largely reflects Zander’s later view of Didymodon (2013, 2019) but with a few changes. Three of Zander’s genera (AithobryumExobryum and Fuscobryum) are nested within generic names published earlier, and therefore, are now viewed as synonyms.

So here is what the Jiménez et al. (2021) study concluded: of the eight clades now recognized at the generic level, seven have a species in California. Tridontium, a genus now comprised of three species restricted to Australia and New Zealand, is not in California. This genus was previously viewed as being monotypic (as T. tasmanicum) and earlier placed in the Scouleriaceae, but clearly excluded from this family by Carter et al. (2014). When I first collected Tridontium many years ago during a trip to Tasmania, I said to myself, this is a pottiad that looks just like a Didymodon. I was at a loss how one could possibly view it related to Scouleria.

Observing species and their habitats in the field can offer different insights than can be obtained from solely examining specimens in herbaria. With all of these proposed realignments, Didymodon as a genus is now viewed as containing between 50–60 species and basically restricted to the Holarctic. It is morphologically a group of species with a central strand, lacking a hyalodermis, and with a green to yellow KOH reaction (Jiménez et al. 2021). Many more recently published species of Didymodon, especially from China (known primarily from type specimens), lack sequence data and are not readily available on loan to other researchers to determine their true affinity.

So here is the revised nomenclature for selected Didymodon species and the different generic placements for California representatives. Most of the species of Didymodon previously listed for California are now in Vinealobryum.

Didymodon rigidulus Hedw.
Geheebia fallax (Hedw.) R. H. Zander [=Didymodon fallax (Hedw.) R. H. Zander]
Geheebia tophacea (Brid.) R. H. Zander [=Didymodon tophaceus (Brid.) Lisa]
Geheebia ferruginea (Schimp. ex Besch.) R. H. Zander [=Didymodon ferrugineus (Schimp. ex Besch.) M. O. Hill
Gertrudiella nevadensis (R. H. Zander) J. A. Jiménez & M. J. Cano [=Didymodon nevadensis R. H. Zander]
Husnotiella revoluta Cardot [=Didymodon revolutus (Cardot) R. S. Williams]
Trichostomopsis australasiae (Hook. & Grev.) H. Rob. [=Didymodon australasiae (Hook. & Grev.) R. H. Zander
Trichostomopsis umbrosa (Müll. Hal.) H. Rob. [=Didymodon umbrosus (Müll. Hal.) R. H. Zander]
Vinealobryum brachyphyllum (Sull.) R. H. Zander [=Didymodon brachyphyllus (Sull.) R. H. Zander]
Vinealobryum californicum (J. A. Jiménez, D. R. Toren & Shevock) R. H. Zander [=Didymodon californicus J. A. Jiménez, D. R. Toren & Shevock]
Vinealobryum eckeliae (R. H. Zander) R. H. Zander [=Didymodon eckeliae R. H. Zander]
Vinealobryum insulanum (DeNot.) R. H. Zander [=Didymodon insulanus (DeNot.) M. O. Hill]
Vinealobryum nicholsonii (Culm.) R. H. Zander [=Didymodon nicholsonii Culm.]
Vinealobryum norrisii (R. H. Zander) J. A. Jiménez & M. J. Cano [=Didymodon norrisii R. H. Zander]
Vinealobryum rubiginosum (Mitt.) J. A. Jiménez & M. J. Cano [=Didymodon vinealis var. rubiginosus (Mitt.) R. H. Zander and Didymodon occidentalis R. H. Zander]
Vinealobryum tectorum (Müll. Hal.) R. H. Zander [=Didymodon tectorum (Müll. Hal.) K. Saito]
Vinealobryum vineale (Brid.) R. H. Zander [=Didymodon vinealis (Brid.) R. H. Zander]
Zanderella purpurea (Müll.Hal.) J. A. Jiménez & M. J. Cano [=Didymodon bistratosus Hébr. & R. B. Pierrot; ≡ Barbula purpurea Müll. Hal.]

Others have asked me, when do I ‘accept’ a new proposed name transfer? Well for me, if I can see differences among related taxa in the field, I am much more inclined and ready to accept the proposed name change. Also, if multiple phylogenetic studies reinforce that position, then I am ready to jump on board. For example, although many bryologists do not recognize the generic splits in Racomitrium, I do. At least to me, I can separate them readily in the field. Of course, these names are getting greater use among North American bryologists because that is how this group was treated in Flora of North America, but not so among bryologists on other continents where a historic application of Racomitrium is still preferred. Same situation among Bryum. Nonetheless, it might take quite a bit of work to recognize these generic splits of Didymodon in the field. Fortunately, there are morphological characters to assist in their recognition back in the lab. Will these genera receive wider use? Only time will tell.

Literature Cited

Carter, B.E., S. Nostratinia & J.R. Shevock. 2015. A revisitation of species circumscriptions and evolutionary relationships in Scouleria (Scouleriaceae). Systematic Botany 39: 4–9.

Crosby, M.R., R.E. Magill, B. Allen & S. He. 2000. A checklist of the Mosses. Missouri Botanical Garden, St. Louis. July 26, 2000 edition, 320 pp.

Hedwig, J. 1801. Species muscorum frondosorum descriptae et tabulis aeneis lxxvii coloratis illustratae. Opus posthumum editum a Friderico Schwägrichen vi.+ 355 pp + p;s 1–77. Leipig. J.A. Barth.

Jiménez, J.A., M.A. Cano and J. Guerra 2021. A multilocus phylogeny of the moss genus Didymodon and allied genera (Pottiaceae): Generic delimitations and their implications for systematics. Journal of Systematics and Evolution doi: 10.1111/jse.12735

Koch, L.F. 1950. Mosses of California: an annotated list of species. Leaflets of Western Botany 6: 1–40.

Norris, D.H. & J.R. Shevock. 2004. Contributions toward a bryoflora of California I. A specimen-based catalogue of mosses. Madroño 51: 1-131.

Zander, R.H. 1993. Genera of the Pottiaceae: Mosses of harsh environments. Bulletin of the Buffalo Society of Natural Sciences 32: 1-378.

Zander, R.H. 2013. Framework for post phylogenetic systematic. St Louis, Zetetic Publications.

Zander, R.H. 2019. Macroevolutionary versus molecular analysis: systematic of Didymodon segregates AithobryumExobryum and Fuscobryum (Pottiaceae), Bryophyta). Herzogia 10: 1–10.

Clevea hyalina (Sommerf.) Lindb. in Southern California

—Chris Wagner


complex thallus
Clevea hyalina, Idlewild, SBNF, CA

Clevea hyalina is a thalloid liverwort first described in 1829 as Frimaldia punicea in Hepaticarum Europaearum (Johann Bernhard Willhelm Lindenberg). The name was changed to Clevea hyalina in 1868 and then reported by Marshall Howe in 1899 for California in “Hepatica and Anthocerotes of California” (Howe 1899) where he also recognized the variety californica. Since then, the species has gone through numerous name changes, becoming Athalamia hyalina in 1954. In 2011, in the document “Phylogeny and Taxonomy of the Complex Thalloid Liverwort Family Cleveaceae Cavers,” Rubasinghe changed the name back to Clevea hyalina. It was then recognized in North America in “A Checklist of the Liverworts and Hornworts of North America” by R. E. Stotler and B. J. Crandall-Stotler in 2017 (Bryologist 80: 405–428).

Clevea hyalina grows on soils of well shaded and moist areas. The Bryophyte Flora of North America treatment for Clevea hyalina is currently in progress by Alan Whittemore with the diagram completed just this past winter on the Bryophyte Flora of North America web site hosted by the Missouri Botanical Garden. Wilf Schofield described it as “grayish to pale green small thalli, 0.5–1.5 cm long, usually less than 1 cm, 2–5 mm wide, forked, with simple pores in the dorsal surface, opening into elongate chambers with chlorophyllose walls, these occupying 2/3 the thickness of the thallus, margins somewhat involucrate with white scales curving over the margins. Dioicous. The receptacle 2–3 (4)-lobed, pale green on a short stalk 0.2–1 cm. long, colourless, with a cluster of white lanceolate scales just below the receptacle, sporangia light brown, ovoid, opening irregularly”. Whittemore describes it as “Epidermis with well-defined pores; ventral scales in several rows, with poorly-defined appendages, sporophytes in dorsal carpocephala”.

First described by Howe, Alan Whittemore’s A preliminary checklist, with keys, of California liverworts and hornworts (December 2020) describes two varieties of Clevea in California again. Clevea hyalina var. hyalina and Clevea hyalina var. californica. The big difference between the two are mainly the size of the pores and the thickness of the pore wall cells on the thallus. Additionally, Howe mentions that Clevea hyalina var. californica can have spores that are more “red” rather than the typical reddish brown to yellow. I am expecting the final detailed description of these taxa to come out when Whittemore completes the treatment.


Figure 1. Historic and current occurrences of Clevea hyalina, herbaria collections, personal herbaria collections and iNaturalist observations

Currently, Clevea hyalina is documented throughout California (Figure 1), with the earliest dates in 1893 and 1896. In Figure 1, the #1 site (Ukiah area) were all collected by Howe 1896 which was the first time the var. californica was identified.

The Consortium of North America Bryophyte Herbaria (CNABH) is one of the most useful tools for understanding a species’ populations and needs. As you can see in Figure 1, there are many observations that have yet to be collected and/or submitted into herbaria as seen with the red stars. Many of these sites are derived from Whittemore’s California key, based on his ‘Representative collections’ and from confirmed sightings not yet submitted to any herbarium such as those on iNaturalist, in addition to one personal observation.

In Southern California, which includes the uppermost county borders of San Luis Obispo, Kern and San Bernardino, along the border of Nevada and down to the border of Mexico, we currently have one historical site in Pasadena and four more recent sites (Figure 2). Site 1 and 4 are both William Doyle collections that are part of his personal herbarium. They are from San Luis Obispo County and the Borrego Palm Canyon area. The two other sites are in the San Bernardino National Forest (SBNF).

Figure 2. Current and historic occurrences of Clevea hyalina in Southern California

The historical site collected by A. J. McClatchie in 1893 shown as CNABH point in which the collection site was in Pasadena, has never been confirmed to still exist since the initial collection (Figure 2).

Site 2 (Figure 2) was documented during the 2015 SoBeFree annual gathering, and this was the first site documented on the San Bernardino National Forest. No specimen has been submitted to any herbarium for accession at this time. Belinda Lo, who submitted an observation to iNaturalist, stated that Ken Kellman identified and preserved a sample for his personal collection (Figure 3). My plan is to go to the site this winter/spring season and make a collection and submit it to a public herbarium.


Figure 3. Clevea hyalina from Site 2 (from Figure 2)

In the spring of this year (2021), I found the second site on SBNF which is the fourth newer site for Southern California (Site #3, Figure 2). The collection will be submitted to the California Academy of Sciences bryophyte collection managed by James Shevock. I attempted to key out to variety but obtaining a cross section of the upper thallus to see those pores proved difficult. I will try again, perhaps after the Clevea treatment by Whittemore has been completed, before finalizing and submitting the collection to an herbarium (Figures 4 and 5 for species photos from this site).

composite of several photos
Figure 4. Clevea hyalina, Site 2, SBNF. Females, males and cross-sections of thallus


spores being presented
Figure 5. Clevea hyalina with mature sporophytes, Site 2, SBNF

The 1st and 3rd sites (Figure 2) are the estimated locations of Bill Doyle’s collections as referenced in the Whittemore Key. (Adelaide Rd. about 3 miles east of jct. with Cypress Mountain Rd., San Luis Obispo Co., Doyle 434) and (Borrego Palm Canyon, San Ysidro Mountains, San Diego Co., Doyle 7078 (herbarium of W. T. Doyle). I do not have any other collection information on these, no date or GPS location. I plan to also attempt to find the southernmost site #4 and make collections for the herbarium.

This research exercise on Clevea hyalina has shown that not all data are being properly recorded and shared. While iNaturalist is another very useful tool, it does not provide the actual specimen that can later be studied. In Southern California liverwort species are most likely being overlooked during botanical surveys. It is known that many botanists overlook the non-vascular species during surveys unless they have some understanding of non-vascular species and know what they need to look for. Having updated data from collections accessioned into herbaria, and thus available, is essential to understanding rarity, trends, and the study of such species. As you can see in Figure 1, all the red stars indicate collections that have not been submitted to public herbaria and are therefore missing from the Bryophyte Consortium, which is only showing older collection data for this species.

We really have no idea as to just how rare this species is in southern California. In Canada, Clevea hyalina is listed as “vulnerable” in the west and “critically imperiled” in the east. We have no special status listings within the United States even though we know this species is rare in some places. The southern California sites are the southernmost known population sites known in the United States including one site in Arizona and one more on the border of Texas and Mexico. Populations then skip Mexico, Guatemala and Nicaragua to pop up again in South America though only rarely.

The more we can add to herbarium collections, the more accurate information will be available for use in the study of the varieties. Herbarium collections assist land managers and other researchers in understanding population trends and potential existence of other populations. With better data we can determine if species protections are needed.

Further surveys will continue in Southern California and will contribute additional herbarium specimens. It is estimated that there are more populations here, but it would still most likely be considered rare in Southern California. An evaluation should begin to determine if this species should be listed as a species of concern. This might encourage people to look for Clevea hyalina during future surveys.


Howe, M. 1899. The Hepatica and Anthocerotes of California. Memoirs of the Torrey Botanical Club 7: 1-208; plates 88-122.

Schofield, W. 2020. In Klinkenberg, B. (editor). E-Flora BC: Electronic Atlas of the Plants of British Columbia []. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. Last accessed: Aug 1st, 2021. (

Whittemore, E. 2020, Bryophyte Flora of North America, Provisional Publication Missouri Botanical Garden, Clevea diagram. Last accessed: Aug 1st, 2021, (

Rubasinghe, S. C. K. 2011, Phylogeny and Taxonomy of the Thalloid Liverwort family Cleveaceae Cavers, xi + 264 pp. University of Edinburgh, Royal Botanic Garden Edinburgh, Edinburgh, Scotland.

Stotler, R. E. & B. J. Crandall-Stotler. 2017. A checklist of the liverworts and hornworts of North America. The Bryologist 80: 405–428.

Whittemore, A. 2020, A preliminary checklist, with keys, of California liverworts and hornworts, (

Stotler, R. E. & B. J. Crandall-Stotler. 2017. A synopsis of the liverwort flora of North America north of Mexico. Ann. Missouri Bot. Gard. 102(4): 574–709.

David Wagner offers his stunning photo with labeled parts of the peristome of Rhytidiadelphus loreus for free non-commercial, educational purposes in the spirit of creative commons. When using it, please give credit to David and repeat the creative commons statement.


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