Moss Medicine

      

By Robert Dale Rogers

INTRODUCTION Evolving from the Ancients   This is the forest primeval. The murmuring pines and the hemlocks, Bearded with moss, and in garments green.   Henry Wadsworth Longfellow Bryophytes, which include mosses, liverworts, and hornworts, are the second largest group of land plants after angiosperms, and among the oldest. Worldwide, there are some 14,000 species of leaf mosses (Bryophyta), more than 6,000 species of liverworts or liver mosses (Marchantiophyta), and 300 species of hornworts or foliage mosses (Anthocerotophyta) (Chandra et al. 2017). Note that wort is from the Middle English wyrt, for “root,” “herb,” “plant.” A checklist by Soderstrom et al. (2016) suggests the total of both liverworts (Marchantiophyta) and hornworts (Anthocerotophyta) includes 7,486 species in 398 genera and 92 families. This number is decidedly low, as other authors suggest closer to 24,000 species worldwide.   The word bryophyte is derived from the Greek bruon, meaning “tree moss,” and phuton, meaning “plant.” The common name moss can be misleading. Spanish moss (Tillandsia usneoides), for example, belongs to the Bromeliaceae family, while reindeer moss is a lichen, spike moss a Selaginella spp., clubmoss a lycophyte, and Irish moss a seaweed.   There is controversy on the use of the plural moss versus mosses. The former is widely used by myself and the general population, but the scientific community deems only mosses as acceptable. The use of moss as a mass noun is to indicate a singular instance of its uniform nature (e.g. the moss blankets the rock) whereas mosses as a plural count noun is used to indicate various species/types of mosses. Both usages are grammatically correct, but it would make sense that mosses is used more often by the scientific community because they would be more inclined to identify and classify the little beings. Consider moose, which is used in both singular and plural senses. But the plural of mouse is mice. Oh well, such is the English language. Bryophytes are distinguished by having no vascular tissue and no roots. They derive moisture from the air like a paper towel, absorbed from a leaf surface the thickness of which is only one cell, and they also extract nutrients from the air.   Hornwort is derived from the hornlike shape of the hornwort sporophyte, which is the multicellular diploid phase (Frangedakis et al. 2022). They are found on all continents in a wide range of climates, ranging from deserts to polar regions. Access to moisture is a limiting factor to growth.   Most bryophytes remain hidden from humans simply because of their less noticeable domains. That may be a good thing, as where they grow does influence their flavonoid content. In one 2017 study (Wang, Cao et al.), it was shown that the flavonoid concentration in ninety samples of bryophytes varied from 1.8 mg/g to 22.3 mg/g. The study also showed that the flavonoid content in liverworts was generally higher than in mosses, with acrocarpous mosses (mosses with an upright growth pattern) higher in flavonoids than pleurocarpous species (mosses with a prostrate growth pattern). Bryophytes growing at low light levels exhibit the highest levels of flavonoids, and those of aquatic species the lowest. Also, the flavonoid content of low-latitude species was higher than those growing at higher latitudes.   The term ethnobryology was first coined by botanist Seville Flowers (1957) in a paper on their use by the Gosiute of Utah. Bryophytes, which have strong antimicrobial activity, have been widely used in traditional medicine for thousands of years for a variety of health conditions, including treatment of the liver, skin, and cardiovascular system. A study by Harris (2008) suggests the medicinal use of bryophytes has been explored mostly by Indigenous peoples of North America (28% of all species) as well as by Traditional Chinese Medicine (27% of all species). In China, for example, 40 species of bryophytes are used for medicine, while in India 22 species (but only those growing in Himalayan regions) are used. Oddly, there is no record of bryophyte use in Ayurvedic medicine.   Celtic traditional medicine, as recorded in the antique 1861 Welsh (Cymry) book The Physicians of Myddfai: Meddygon Myddfai, mentions using the river startip liverwort, Scapania undulata (Wagner et al. 2020). In a promising study by the National Cancer Institute, the antitumor properties of 123 mosses, 13 liverworts, and 1 hornwort was assessed (Spjut 1986). The research continues.   And yet, by and large, byrophytes are largely ignored by the medical community despite growing evidence of their ability to alleviate a number of chronic conditions. Perhaps this is partly because bryophytes do not produce flowers or seeds, drawing little attention from most botanists.   As a retired clinical herbalist, my interests lie in their medicinal potential for restoring human and animal health, as well as their potential to assist in the survival and well-being of our planet. The study of bryophytes is over a century old, but it’s only been in the last 40 years that we have seen a tremendous accumulation of information on their chemistry and potential medicinal uses.   As with lichens, there has been a decline in bryophyte cover and richness, which is an indicator of our changing environment, in particular the heavy metal content in air pollution. Many people have heard of Oetzi, the Neolithic Tyrolean Iceman. His frozen body was uncovered in 1991 when retreating glaciers exposed him to hikers in the Austrian-Italian Alps. Along with his body was the discovery of 75 or more subfrozen bryophyte fossil species, including ten liverworts. Today, only 21 of these bryophytes grow in the same area (Dickson et al. 2019). At present, bryophytes are mainly used more prosaically as material for seed beds, fuel, food, pesticides, nitrogen fixation, gardening, construction, clothing, furnishing, packing, and soil conditioning.   THE PEATLAND PURIFIER   Mosses sequester carbon, one of their many gifts. Sphagnum spp. mosses, for example, soak up massive amounts of carbon dioxide, far exceeding the rate of sequestration by all the rainforests in the world combined according to bryophyte expert Annie Martin (2015). Peatlands contain as much carbon as is present in Earth’s entire atmosphere, sequestering between 198 and 502 billion tons of carbon. Peat moss, especially sphagnum mosses, covers 85% of the province of Quebec, some 11.6 million hectares. One half square meter of moss sequesters one kilogram of carbon dioxide. Put another way: mosses sequester 6.43 billion tons of carbon annually from the atmosphere, or six times the carbon from altered lands (cultivated, agricultural lands) (Eldridge et al. 2023). And consider that mosses cover 9.4 million square kilometers of Earth’s surface!   As one example of the great potential of bryophytes, Green City Solutions, a German company, utilizes the dust-cleansing properties of mosses to purify urban air. They have developed several products, including something called City Tree, which cleanses air for 100,000 people every hour, removing 82% of fine dust and cooling the returned air by up to 4.5° F / 2.5° C. Their larger units, City Breeze and Wall Breeze, are currently in development.   Sphagnum moss communities host numerous microorganisms, including microbial polyesterases. Work by Muller et al. (2017) identified six novel esterases, which were isolated, cloned, and heterologously expressed in Escherichia coli. The enzymes hydrolyzed not only common esterase substrates, but also polybutylene adipate terephthalate, or PBAT, a common material used in biodegradable plastics. The widespread use of synthetic polyesters requires the development of new sustainable technology solutions to enable recycling.   There is currently a fear that peat bogs are contributing to the rise in methane, but this has been debunked by recent findings (Wilson et al. 2016). Peat moss regenerates quickly, is easily harvested, has a low sulphur content, and its heating value is superior to wood. Moreover, peatlands, when drained and neutralized of acidity, are prolific producers of leaf and root vegetables. Over 100,000 acres throughout Canada are currently under agricultural use, supplying a large amount of produce for Toronto and Montreal. In Germany, sphagnum farming is replacing drainage-based peatland agriculture to help tackle downstream pollution and climate change (Vroom et al. 2020).   On the other hand, the destruction of peatlands, bogs, and fens by the petroleum industry has created a unique ecological and environmental challenge. The re-creation of wetlands after their destruction by Athabasca oil sands companies in northeastern Alberta, Canada, will require the rapid cultivation of mosses, including fast-growing Sphagnum species. Fortunately, clonal in vitro cultivation of various species, including blunt-leaved bogmoss, Sphagnum palustre, is greatly increased some ten- to thirtyfold with the additions of sucrose and ammonium nitrate (Beike et al. 2015). These kinds of advances in biotechnology can help prevent the exploitation of wilderness mosses while also advancing the production of unique compounds for natural health and pharmaceutical benefit. Moss Medicine by Robert Dale Rogers, RH(AHG), published by Inner Traditions International and Bear & Company, © 2026. All rights reserved.  http://www.Innertraditions.com Reprinted with permission of publisher.   Author Bio: Robert Dale Rogers, RH(AHG), an herbalist with more than 50 years of experience, is the author of more than 60 books, a professional member of the American Herbalists Guild, and on the editorial board of the International Journal of Medicinal Mushrooms. A former clinical professor in family medicine, he lives in Camrose, Alberta, Canada.