Well, Well, What Do We Have Here? A Tale of Two Acorus Species

by Erin Holden

Tall, thin green leaves with a whitish-greenish spadixWhile doing research for a presentation on herbal uses of native plants, I decided to look more into a plant I’d learned about in herb school, sweet flag (Acorus calamus). This strongly aromatic aquatic plant has long been my favorite warming digestive bitter for those times when I overindulge in a huge meal (I’m looking at you, Thanksgiving). The flavor is warm, pungent, bitter, and spicy in a black-peppery way – the flavor sort of fills up your mouth and is warm all the way down to your stomach. But as I dug deeper into the research, I discovered I’d been wrong all this time about the origin of the Acorus species I’d been using. It turns out that A. calamus is native to Europe, temperate India, and the Himalayan region, while the native species is A. americanus (also called sweet flag), although the two species look so similar that even some scientists are unsure of which species they’ve studied and reported on. There still isn’t much consensus among taxonomists as to what differentiates these two – some even classify them as the same species (Boufford,1993; eFloras, 2008). Let’s take a deeper look at the similarities and differences between these two plants. 

There are many common names for sweet flag from all over the world (Daglan, 2014), many of which describe either the flavor of the root (like bitter, sweet, pepper) or its watery habitat:

Muskrat_eating_plant Linda Tanner via wikimediaAbenaki: mokwaswaskw (muskrat plant)

Ayurvedic Tradition: vacha 

Cheyenne: wi’ukh is e’evo (bitter medicine) 

Chinese Medicine: shui chang pú (watery flourishing weed)

English: sweet flag, calamus 

Hudson Bay Cree: pow-e-men-arctic (fire or bitter pepper root) 

Penobscot and Nanticoke: muskrat root

Micmac: ig gig’wesukwul (muskrat root)  

Pawnee: kahtsha itu (medicine lying in water) 

Many Native American names connect Acorus with muskrats. According to Sue Thompson’s dissertation on Acorus (as reported by Daglin, 2014): 

There seems to be “a closely linked ecological relationship between Native Americans trapping muskrats and using Acorus, muskrats eating Acorus, and Acorus. Muskrat feeding habits may in part be responsible for the dispersal of Acorus, and Native Americans may have intentionally planted Acorus both for their own medicinal use and to ensure food for the muskrat, which was economically valuable to them (Morgan 1980). Thus, the many Native American names for Acorus, which involve muskrat as a root word, may reflect an important economic and ecological relationship among man, plants, and other wildlife.”

A border planting of tall, thin green Acorus calamus leavesBoth species are perennial, grow in zones 4 to 10, have 1’–3’ tall iris-like leaves, and can spread 1’–2’. They bloom April through June, and like full sun to part shade. The inflorescence is a green spadix with no spathe (a spathe is a hood-like structure, like the white part of a peace lily). Both A. americanus and A. calamus are freshwater aquatic plants that grow in medium to wet soil and can grow in up to nine inches of water. They’re both easily propagated by root/rhizome divisions in the spring. Since they are aquatic plants, they can be used in water gardens, ponds, or rain gardens. They can also grow in regular garden beds as long as they get adequate water, so they’re very versatile if you’re looking for tall, straight leaves (Missouri Botanical Garden, 2022).

Although the two species look very much alike, there are some subtle differences you can use to tell them apart. A. calamus has leaves with one prominent vein and undulate (wavy) margins, does not produce fruit, and will “appear to have a shriveled ovary” in late summer, whereas A. americanus has leaves with two to six veins and smooth margins, produces small green berries, and has swelling ovaries in late summer (Dalgin, 2014).

There are also some unseen differences between the two. It turns out that A. americanus is a fertile diploid species and contains almost no phenylpropanoids, a chemical family whose members play a role in the flavors and aromas of cinnamon, cloves, nutmeg, and sassafras. A. calamus is a (mostly) sterile triploid (there are some populations of a fertile diploid phenotype in Asia that are morphologically distinct from the North American A. americanus). In addition, 13% of its volatile oil fraction is made up of those phenylpropanoids, one of which is β-asarone.

Botanical illustration of Acorus calamusThis chemical distinction is important, because β-asarone has demonstrated procarcinogenic tendencies (meaning it could metabolize into a cancer causing compound), and the FDA has banned the use of “calamus, calamus oil, or extract of oil in food,” although these studies used high levels of isolated β-asarone and not “suggested doses of the whole plant in terms of mg/kg of body weight” that an herbalist would recommend. However, since A. americanus has little to no β-asarone, it’s been suggested that this species is safe to consume (Dalgin, 2014).

Sweet flag is an important plant for many native peoples. One writer said it is “considered so sacred [to the Cheyenne] that only qualified Sundance priests [can] collect it,” and it “may be the most important herb in Penobscot pharmacology” (Dalgin, 2014). 

Historically, the Dakota used a paste on their faces to “instill fearlessness and provide stamina” in battle and chewed the rhizomes to enhance endurance “during the wars of the 20th century” (Dalgin, 2014). 

Other uses for the plant include: colds, flu, and sore throat; as a tonic; for intestinal pain and as a carminative (dispels gas); as a stimulant when tired; toothache; an analgesic for muscle cramps/spasm; and in ceremonial/religious rituals.

Tall, thin leaves of Acorus americanus growing along the bank of a streamColonists also used Acorus, and Eclectic physicians (doctors in the 1800s) incorporated it into their materia medica (list of medicinal substances). Eventually, it made its way into the first edition of the  Dispensatory of the United States in 1833 (Osol et al, 1833), which cataloged drugs used by U.S. pharmacists at the time. These groups used it pretty much the same way that Native Americans use it: as a carminative, for weak digestion and flatulent colic, as a sialagogue (stimulates saliva production) and as “breath perfume,” a warming aromatic bitter, and externally for ulcers that wouldn’t heal (Dalgin, 2014). 

Some modern herbalists who use both species say that, because of its higher volatile oil content, A. calamus targets the gastrointestinal system more specifically, while A. americanus has a “more balanced” action on the whole body—working equally on the gastrointestinal and nervous system, as an expectorant (which helps clear gunk from the lungs), spasmolytic (calms spasms), and antitussive (Daglin, 2014).

Now that I know about A. americanus and its different effects on the body, I’m interested in experimenting with the two species. I’ve also planted it out in the Native American bed in the National Herb Garden. I wonder if we should also invest in a muskrat.

Photo Credits: 1) Acorus calamus inflorescence (E. Holden); 2) Muskrat (Linda Tanner, via Wikimedia ); 3) Acorus sp. used as a mass border planting (KENPEI, via Wikimedia  ); 4) Two prominent veins and smooth leaf margins of A. americanus (E. Holden); 5) The prominent midvein and undulate leaf margins of A. calamus (E. Holden); 6) Botanical illustration of A. calamus (Creative Commons, Rawpixal LTD); 7) Acorus americanus growing along a stream bank (Ryan Hodnett, via Wikimedia)

Medicinal Disclaimer: It is the policy of The Herb Society of America, Inc. not to advise or recommend herbs for medicinal or health use. This information is intended for educational purposes only and should not be considered as a recommendation or an endorsement of any particular medical or health treatment. Please consult a health care provider before pursuing any herbal treatments. 

References 

Boufford, D. E. 1993+. Acorus. In: Flora of North America Editorial Committee, eds. Flora of North America North of Mexico [Online]. 22+ vols. New York and Oxford. Vol. 3. Accessed 10/5/22. Available from http://beta.floranorthamerica.org/Acorus

Dalgin, R. 2014. Acorus calamus and Acorus americanus. Integrative Herbalism: Journal of the Vermont Center for Integrative Herbalism. Summer, 30-78.

eFloras. (Internet). 2008. Acorus calamus. Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA. Accessed 10/5/2022. Available from http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200027130

Lady Bird Johnson Wildflower Center. (Internet). 2015. Acorus americanus (Raf.) Raf. Accessed 1/7/2022. Available from https://www.wildflower.org/plants/result.php?id_plant=ACAM

Missouri Botanical Garden. 2022. Acorus calamus. Accessed 1/7/2022. Available from https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=276172

Orsol, A., C. H. LaWall, F. Bache, G. B. Wood, G. E. Farrar, H. C. Wood Jr., and J. P. Remington. The dispensatory of the United States of America. Grigg & Elliot: Wisconsin. Available from https://www.google.com/books/edition/The_Dispensatory_of_the_United_States_of/xikzAQAAMAAJ?hl=en&gbpv=1


Erin is the gardener for the National Herb Garden at the U.S. National Arboretum in Washington, D.C. She is a member of the American Herbalists Guild, United Plant Savers, and a member-at-large of the Herb Society of America.

Who Was That Guy?

By Chrissy Moore

wp-LostAmazon_backcoverWe’ve likely all had the experience of never having heard of something your whole life, and then suddenly you hear about that thing everywhere. A while back, I was putting together a presentation on cacao research but couldn’t find a photo of the botanist I would be discussing. So, I had to use a placeholder image of some random fellow who happened to be looking at plants with a couple of Indigenous tribesmen in the Amazon. “That’ll have to do for now!” I thought, as I had no idea who the stand-in fellow was and didn’t have time to research him prior to delivering the presentation. But, I acknowledged my photographic hack to the audience and moved on, not giving it another thought.

A week later, one of the audience members emailed me the exact picture I had used, which she stumbled upon in an old copy of The Herbarist (No. 53., 1987), the annual publication of The Herb Society of America. What a coincidence! Come to find out, that “random fellow in the Amazon” was Dr. Richard Evans Schultes. But, still…who was that guy? Clearly, he was someone of importance, but for what? I tabled the inquiry for the time being. Shortly thereafter, one of my volunteers happened to forward me a link to a blog post about the Oakes Ames Herbarium at Harvard University. And whose name appeared in the post? Yep. Richard Evans Schultes. Him again? I decided it was time to go on my own hunt, and lo’ and behold, I found his name practically everywhere in the botanical world. Little did I know that Schultes was a famous 20th century taxonomic botanist and ethnobotanist; Harvard University professor of economic botany; curator, then executive director, of the Botanical Museum of Harvard University; and the one who is considered the father of modern ethnobotany. In other words, plantsman extraordinaire! How had I not come across his name after all these years in the herb world? Boy, did I feel silly. But, you don’t know what you don’t know until you know it! 

rivea_corymbosaSchultes was born in 1915 in Boston, Massachusetts, but spent many years of his life studying plants used by Indigenous peoples, primarily in the Americas. He is known for his work on medicinal and toxic plants, particularly those with hallucinogenic and entheogenic properties. (Hallucinogenic “refers specifically to plants or drugs which induce true hallucinations through the action of deleriant anticholinergic substances such as naturally occurring tropane alkaloids,” while entheogenic refers to “plants and substances which can induce transcendent mystical or spiritual experiences nearly always involving visions….It is associated with a range of psychoactive plants, specifically when used in religious or spiritual…contexts, be they hallucinogens, psychedelics, dissociatives, or others” (Hay et al., 2012).) His deep dive into Amazonian plants began while seeking out wild, disease-resistant Hevea (natural rubber) species in the Western Hemisphere for the United States government during World War II. (During the war, the Southeast Asian rubber sources were cut off, and new sources were needed.) Though he worked for the U.S. Department of Agriculture for twelve years, Dr. Schultes’ research branched out to include many other plants with varying economic or ethnobotanical uses. All the while, he maintained a focus on hallucinogens of plant origin. During his career, Schultes collected over 24,000 herbarium specimens and is credited with introducing 300 plants not previously known to science. 

In one of his papers, Schultes notes, “In view of the number of plant species, variously estimated at from 400,000 – 800,000 species, those that have been used as hallucinogens are few; probably no more than 60 species of cryptogams [spore-producing] and phanerogams [seed-producing]….Only 20 may be considered important” (Schultes, 1969).

Lophophora williamsiiSome of his most well-known research subjects were peyote cactus (Lophophora williamsii), used for ritual by the Kiowa tribe in Oklahoma; ayahuasca, an entheogenic botanical brew used by Indigenous tribes of South America; and the numerous plants used to make curare, “a mixture of naturally occurring alkaloids found in various South American plants and used as arrow poisons” (ScienceDirect, 2021). After decades of research into its mode of action by many scientists around the world, curare was applied to surgical procedures in the 20th century, along with anesthesia, as a muscle relaxant during operations until safer synthetic analogues were discovered (Burr and Leung, 2014).

“I have tried several of the Indian hallucinogens, in part because the Indians consider them sacred plants and it would have been an unpardonable rudeness to refuse them when the Indians were kind enough to offer them to me during a ceremony” (Schultes, 1994).

By all accounts, Schultes was a die-hard ethnobotanist, who defined it thusly:

 “[It is] the complete registration of the uses of and concepts about plant life in primitive societies… comprising aspects of botany, anthropology, archeology, plant chemistry, pharmacology, history, geography, and sundry other tangential fields of the sciences and arts” (Schultes, 1988).

Schultes5-572x768His knowledge of the field went beyond just the cultural or botanical, but also landed squarely in the geographical as he sought to document the locations of plants and people. His journal notes and maps were indispensable for recording hard-to-get-at information, including language documentation of the tribes with whom he worked.

After living with and learning from the Indigenous populations in Amazonia for more than ten years (he concentrated on the northwest Amazon region of Colombia), Dr. Schultes returned to the United States and taught economic botany classes at Harvard University for decades, inspiring hundreds of students with his understanding of people and the plants they use. He also contributed hundreds of papers to various scientific publications, as well as authored eight books.

During his career, Schultes noted the rapid destruction of the Amazon rainforest and strongly advocated for its conservation, not just for the plants themselves, but for the knowledge that the Indigenous peoples held of those plants, both of which were disappearing at an alarming rate.

“It is therefore our responsibility – nay, our duty – to put ourselves in the forefront of ethnobotanical conservation. We cannot allow such precious funds of knowledge to become extinct” (Schultes, 1988).

He also understood the potential loss of knowledge yet to be discovered and encouraged continued botanical, pharmacological, and ethnobotanical research throughout the Amazonian basin.

Schultes_amazon_1940s-593x768Schultes was a lover of people, whether they were the tribespeople with whom he forged friendships or the students he mentored at university. His knowledge was profound, and scores of plants share his name. His conservation efforts were acknowledged through numerous awards during his lifetime, including the World Wildlife Fund’s Annual Gold Medal in recognition of ethnobotanical conservation, as well as a 2.2-million-hectare tract of land in Colombia. Dr. Schultes was also an honorary member of the New England Unit of The Herb Society of America! Not surprisingly, his impact has been felt the world over. I may have only recently heard of this tremendous ethnobotanist, but he’s definitely taken me on a botanical journey I’ll not soon forget.

Photo credits: 1) R.E. Schultes in South America (Wade Davis/Earth Aware Editions); 2) Turbinia corymbosa (syn. Rivea corymbosa) botanical illustration (R.E. Shultes); 3) Lophophora williamsii (peyote cactus) (Wikimedia Commons); 4) Schultes’ hand drawn map in his field notebook (Harvard University Botany Libraries); 5) Schultes with Salvador Chindoy (left), a renowned Kamëntsá healer from Sibundoy Valley of Colombia (Archives of the Economic Botany Library of Oakes Ames, Harvard University).

References

Burr, S.A. and Y.L. Leung. 2014. Curare (d-Tubocurarine). Encyclopedia of Toxicology (Third Edition). Academic Press.

Curare – An Overview. https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/curare. Accessed 14 June, 2021.

Davis, Wade. The Lost Amazon: The Photographic Journey of Richard Evans Schultes. San Francisco: Chronicle Books, 2004. 160 pp. ISBN# 0-8118-4571-0

Hay, A., Gottschalk, M., & Holguín, A. 2012. Huanduj: Brugmansia. Royal Botanic Gardens, Kew: Richmond, United Kingdom

Kahn, E. J. “Jungle Botanist [Richard Evans Schultes]”. The New Yorker. v. 68: pp. 35-58. 1992.

Schultes, Richard Evans. “Burning the Library of Amazonia.” Sciences 34, no. 2, pp. 24. 1994.

Schultes, Richard Evans. “Hallucinogens or Plant Origin.” Science, New Series, Vol. 163, No. 3864 (Jan. 17, 1969), pp. 245-254. www.jstor.org/stable/1725088, accessed 08 Jan 2020.

Schultes, Richard Evans. “The Medicine Man: Herbalist Superb.” The Herbarist, No. 53. 1987.

Schultes, Richard Evans. “Primitive Plant Lore & Modern Conservation”. Orion Nature Quarterly; v. 7, No. 3, Summer 1988. New York, NY: Myrin Institute, 1988b.

https://news.harvard.edu/gazette/story/2003/09/richard-evans-schultes/. Accessed 3/31/2021.

https://blog.biodiversitylibrary.org/2020/08/richard-evans-schultes.html. Accessed 3/31/2021.

Medicinal Disclaimer: It is the policy of The Herb Society of America, Inc. not to advise or recommend herbs for medicinal or health use. This information is intended for educational purposes only and should not be considered as a recommendation or an endorsement of any particular medical or health treatment. Please consult a health care provider before pursuing any herbal treatments.


Chrissy Moore is the curator of the National Herb Garden at the U.S. National Arboretum in Washington, DC. She is a member of the Potomac Unit of The Herb Society of America and is an International Society of Arboriculture certified arborist.

HSA Webinar: The Game of the Name: Taxonomy and Nomenclature Explained

By Jen Munson, Education Chair

Linneaus for BlogWhen I first joined The Herb Society of America (HSA), it was a struggle to distinguish between parsley, thyme, basil, dill, and pretty much all of the common culinary herbs outside of mint. On top of that, I couldn’t tell you what herbs paired best with what foods. Once I had reached some stable grounds on the basics, my HSA friends then started throwing botanical names at me and their importance. It was then that I wanted to run screaming into the streets in confusion. 

If you identify at all with my confusion–or even if you don’t–plan on attending the upcoming HSA Webinar titled, “The Game of the Name: Taxonomy and Nomenclature Explained” with  garden writer, speaker, and educator Debra Knapke. This webinar is being held on Thursday, June 18, 2020, at 1pm EST. During the webinar, Debra will delve into the complex world of nature and help navigate the troubled waters of plant relationships and plant names. In this session, she will help make sense of two systems that, at their hearts, are simple and logical. 

Our webinars are free to members and $5.00 for guests. Visit https://www.herbsociety.org/hsa-learn/hsa-webinars or click here to sign up. Become a member today and enjoy all of our webinars for free. You’ll also be entered into a raffle for a free educational conference registration to our 2021 conference being held in Baton Rouge, LA, from April 29th – May 1st, 2021.

About Debra Knapke

Debra KnapkeThere is nothing Debra Knapke loves more than inspiring people to get out and garden in an eco-conscious way. Known as “The Garden Sage,” Debra is a popular speaker at professional symposia, as well as gardening events throughout the Midwest. She is active with several professional organizations and served as the Honorary President of The Herb Society of America from 2014-2016. Debra has written five books, numerous articles and blogs on Heartland Gardening, has mentored the future of the landscape industry at Columbus State Community College for 24 years, provides garden design consulting in her spare time, and has crammed an amazing variety of perennials, trees, shrubs, and edibles into the 2/3-acre lot surrounding her home.


Jen Munson is The Herb Society of America’s Education Chair. She discovered herbs when she stumbled upon her local unit’s herb and plant sale and hasn’t looked back since. Just recently, she celebrated being a member of the NorthEast Seacoast Unit for 15 years!