Medicinal Plants in the Morgan Arboretum

Dominant tree species within a forest have resounding effects on the developmental direction an ecosystem takes. Different types of trees can affect the soil properties, water, light availability, and in our case, understory growth. A large portion of understory plants have medicinal properties, making them of special interest to humans both historically, having been used by Indigenous communities for centuries, and possibly in the future as sources of new medications, especially with the growing trend towards ‘natural’ remedies (Ehrlich 2013). For our project we asked the question: “What understory medicinal plants are present based on dominant tree species in the Morgan Arboretum, and what is the local biodiversity of these plant species?”. Although medicinal plants comprise a wide variety of species, we are focusing on the Canada Mayflower, Solomon’s Seal, Baneberry, and Twisted Stalk.


To test our hypothesis that we would find more biodiversity of medicinal plants in mixed wood deciduous forests we used multiple 100 meter long transects. They extended into the forest at random intervals, perpendicular to a demarcated pedestrian trail on which we observed our tree species. We first identified and recorded the diameter at breast height of the tree species present along our transects. Then we identified the herbaceous species, noting the ones that were recorded to have some medicinal value. Each species had to be within a meter of the transect line on the ground, and their position was recorded. Each transect was located within the Morgan Arboretum, in Beech Maple, sugar maple and coniferous forests. We also observed and recorded necessary information required for the later identification of unknown species. After collecting enough data, we were then able to discern which medicinal species were most prominent among specific types of trees.

3Figure 1. The green stars indicate transects 1A and 1B-Beech maple forest. Red stars indicate transects 2A, 2B and 2C-coniferous forest. The black stars are transects 3A, 3B and 3C- Sugar maple forest.

Natural history

The Canada Mayflower, or Wild lily-of-the-valley (Maianthemum canadense) is a small, perennial plant with two to three smooth heart-shaped leaves. In the spring they have small white flowers. It grows in cool woods, in deciduous, coniferous, and mixed forests, as well as clearings throughout Quebec, except for far North. Some individuals do not produce flowers, and is simply a single leaf rising from rhizomes that form continuous undergrowth. The berries are edible but can be purgatives in excess. The Canada Mayflower was also used by Amerindians as an infusion to relieve headaches and as a gargle for sore throat (Montreal Botanical Garden).

1Figure 2. a) Maianthemum canadense. Commonly known as The Canada Mayflower, found in our first transect of the Morgan Arboretum. b) Polygonatum multiflorum. Commonly known as Solomon’s Seal, also found at the first transect of the Morgan Arboretum.

One of the most prevalent of the observed medicinal plants is Polygonatum multiflorum, commonly known as Solomon’s Seal. The plant is not native to Canada and is a perennial that typically grows anywhere and prefers lighter soil and a shady spacial distribution (A Modern Herbal). The roots and the shoots are of medicinal significance. The species is most well known for treating pulmonary consumption and bleeding lungs. However, it can also act as an astringent, demulcent, or tonic to treat menstrual pains, stomach inflammation and dysentery.

White Baneberry, Actaea pachypoda, is a perennial also known as “Doll’s-eyes” due to its distinctive round white berry with a black spot that resembles a pupil, carried by thick, bright red pedicels. It is present only in Southern Quebec and Saguenay, and prefers rich woods, maple groves, and the edges of rivers. Despite its toy-like appearance, the berry is highly poisonous and purgative. The root was once used to make a tea for women who had just given birth for labour pains, as well as for headaches, coughs, menstrual irregularities, colds, and constipation (Montreal Botanical Garden).

2Figure 3. a) Actaea pachypoda. Also known as Baneberry, found at our second transect of the Morgan Arboretum. b) Streptopus amplexifolius, commonly known as Twisted Stalk. This sample was found in the Morgan Arboretum at Transect 2C.

Streptopus amplexifolius is a perennial better known to some as Twisted Stalk. It is also called Wild Cucumber because of the taste of the edible green shoots. The plant also produces red to yellow berries, which are edible and have a taste similar to watermelon. In significant quantities, the berries can be used as a laxative or a purgative, but most often the root and foliage are used as a tea. This treats a wide variety of ailments such as an analgesic for internal pains, to induce labor, and to treat kidney problems and gonorrhea (Montana Plant Life).

Scientific Context

The dynamic of diversity and abundance of herbaceous plants in the understory are strongly influenced by tree cover. The variables on which tree cover depends are stand composition, time since major disturbances and available sunlight (Bartemucci P., 2006). A dense overstory usually composed of hardwoods and conifers will have a negative effect on understory vegetation as the amount of transmitted light and precipitation, direct or throughfall, reaching the forest floor are limited (Elsevier, 2008). For these reasons, young mixed deciduous forests allow for more light transmission to the ground and soil moisture regardless of disturbances or topography. Nonetheless, an “old” climax forest will have a steady herbaceous composition. Although the climax forest will be less diverse, as the factors affecting the herb layer are more stable (Brewer R., 1980). Furthermore, studies show that the diversity present in coniferous forests is essentially due to two factors. The first is the amount of precipitation reaching the ground rather than solar radiation, since the canopy density doesn’t change throughout the seasons (Wiley , 1969). The second factor is a lower soil pH, which can often impact what grows in the understory (Berger A. & Puettmann K., 2000). There are other variables to consider such as soil properties other than pH, and factors related to the herbaceous species like their growing season or their tolerance to shade (Brewer R., 1980). Deciduous forests host a lot of spring ephemerals that benefit from the increased sunlight in late-spring and early summer before the canopy reforms (Moore M., & Vankat J., 1986). The vertical profile of light transmission exhibits a decent impact on understory diversity but due to the complexity of the subject no clear conclusion have been drawn so far (Bartemucci P., 2006).  Within this ecological research there is not a lot known on how the specific local forest types such as Beech, Maple, and Spruce, affect the medicinal biodiversity on the forest floor. Our goal is to fill in these gaps of information so that these relationships can be applied on a local forest system level.



Anderson R. C. “Herbaceous Response to Canopy Cover, Light Intensity, and Throughfall Precipitation in Coniferous Forests.” Ecology 50.2 (1969): 255. Web.

Barbier S. “Influence of Tree Species on Understory Vegetation Diversity and Mechanisms Involveda Critical Review for Temperate and Boreal Forests.”Forest Ecology and Management 254.1 (2008): 1. Web.

Bartemucci P. “Overstory Influences on Light Attenuation Patterns and Understory Plant Community Diversity and Composition in Southern Boreal Forests of Quebec.” Canadian Journal of Forest Research / Revue Canadienne De Recherche Forestire 36.9 (2006): 2065. Web.

Berger A. L., Puettmann K. J. “Overstory Composition and Stand Structure Influence Herbaceous Plant Diversity in the Mixed Aspen Forest of Northern Minnesota.” The American Midland Naturalist, vol. 143, no. 1, 2000, pp. 111–125. http://www.jstor.org.proxy3.library.mcgill.ca/stable/3082988.

Brewer, Richard. “A Half-Century of Changes in the Herb Layer of a Climax Deciduous Forest in Michigan.” Journal of Ecology, vol. 68, no. 3, 1980, pp. 823–832. http://www.jstor.org.proxy3.library.mcgill.ca/stable/2259458.

“Clasping-leaved Twisted-stalk – Streptopus Amplexifolius.” Clasping-leaved Twisted-stalk – Streptopus Amplexifolius. Plant-life.org, n.d. Web. 28 Oct. 2016. <http://montana.plant-life.org/species/strepto_ample.htm&gt;.

Moore M. R., Vankat J. L. “Responses of the Herb Layer to the Gap Dynamics of a Mature Beech-Maple Forest.” The American Midland Naturalist, vol. 115, no. 2, 1986, pp. 336–347. http://www.jstor.org.proxy3.library.mcgill.ca/stable/2425870.

  1. Grieve. “Solomon’s Seal.” A Modern Herbal. Botanical.com, n.d. Web. 28 Oct. 2016. <http://www.botanical.com/botanical/mgmh/s/solsea63.html&gt;.
  1. D. Ehrlich SE. 2013. Herbal medicine [Internet]. Phoenix: A.D.A.M., Inc.; [2015 June 11, cited 2016 Sept 27]. Available from: http://umm.edu/health/medical/altmed/treatment/herbal-medicine

Webmaster. “Plant of the Week.” Twisted Stalk. United States Department of Agriculture, n.d. Web. 28 Oct. 2016. <http://www.fs.fed.us/wildflowers/plant-of-the-week/streptopus_amplexifolius.shtml&gt;.

“Wild Lily-of-the-valley, Canada Mayflower.” Space for Life. Espace Pour La Vie, n.d. Web. 28 Oct. 2016. <http://espacepourlavie.ca/en/biodome-flora/wild-lily-valley-canada-mayflower&gt;.

“White Baneberry.” Space for Life. Espace Pour La Vie, n.d. Web. 28 Oct. 2016. <http://espacepourlavie.ca/en/biodome-flora/white-baneberry&gt;.


2 comments on “Medicinal Plants in the Morgan Arboretum

  1. I was surprised to read that Solomon’s seal is not native to Canada, and am a little confused by this statement. While Polygonatum multiflorum is indeed a Eurasian species, there is also a native species Polygonatum biflorum, that is native to Québec, Ontario, and E. North America. Both look similar, with similar heights and fruits, and even similar medicinal uses.

    Since the arboretum is a fairly natural environment, would it not be more likely that it be the native P. biflorum species? That would explain its abundance. P. biflorum is also known to grow in “rich woodland soil but quite versatile and will do well at the base of trees.” http://www.wildflower.org/plants/result.php?id_plant=POBI2

    I don’t know much about this type of plant, but the species caught my eye, so I thought I’d inquire about how you came to your conclusion that the species observed was P. multiflorum not P. biflorum.

    • Hello, and thank you for your insightful response! While P. biflorum and P. multiflorum may be different species with different ranges, for our medicinal purposes, their phytochemical properties are exactly the same. However, due to the literature often siting P. multiflorum (as it’s an old world species, and thus most of the existing extensive phytochemical studies on Solomon’s Seal site it over P. biflorum), we chose to site this plant over the native species. Additionally, since the possibility of P. multiflorum growing in the Arboretum is still high (note other non native species, such as Buckthorn or Bittersweet Nightshade), we cannot be completely certain as to which species we have. The “bi” and “multi” aspects of the species names do not necessarily denote exactly how many flowers each species is supposed to have on each stalk, and thus can vary. We were also observing these species well into autumn, when neither would be flowering, and had very few identifiable characteristics. Therefore, we put most of our efforts into distinguishing Polygonum spp. from Maianthemum racemosum (False Solomon’s Seal), a native and prolific look-alike.

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