Poisonous Plants of Texas
Texas is a beautiful Southern state in the United States of America. Despite the extremely hot summers and high temperatures, this state can easily decorate its hills and the sides of roadways with rich, colorful, and vibrant botanicals. Although many of them are safe and even edible, there are some native Texas plants that are poisonous. As herbalists and students of herbalism, it is vital to understand the proper identification of botanicals to ensure your safety and the safety of others.
The first Texas native poisonous botanical I would like to cover is probably the MOST important one of them all and extremely important for anyone living in Texas to learn about; water hemlock. Water hemlock (Cicuta maculata L.) is considered to be the deadliest plant in North America. The whole water hemlock plant is toxic, with the roots and the base of the stalks containing the highest concentrations. Unfortunately, this poisonous botanical is commonly mistaken for wild carrot (Daucus carota) which also belongs to the parsley family of plants. It is said that victims who are poisoned by water hemlock can chew their tongues to shreds and have convulsions which leads to a quick death because the poison has a direct effect on the central nervous system (Elpel, 2013, p. 180). Despite water hemlock being considered the deadliest plant in North America, it is actually listed in the Pocket Manual of Homoeopathic Materia Medica & Repertory by William Boericke M.D., but under the Latin name of Cicuta virosa because they are referring to the water hemlock that is found in the northwest areas of North America, not in Texas. Boericke states that indications for the use of water hemlock include convulsions with a bending of the head, neck, and spine backwards, pupils that are dilated, muscular spasms, vertigo, spasms of the oesophagus, and many more (Boericke, 2005, pp. 201–203) Historical uses of water hemlock can be dated as far back as Greek literature as well as in medieval Latin literature. The name Conium maculatum came from Linnaeus in 1737, attributing it to the Greek word Konas which means “to whirl about”. Linnaeus chose this word because the plant can cause vertigo and death when eaten. (Grieve, 2018). For individuals who suspect being poisoned by water hemlock, treatment is similar to narcotic overdoses where the thorough evacuation of the stomach contents is crucial. The use of zinc as an emetic is also noted due to its quick actions. Other treatment options are noted, but getting emergency medical attention and contacting poison control would be my first course of action (Kress, 2019). Water hemlock can be identified by having a smooth and erect round-umbel. This means that the pedicels (stalk) arise from a common point, similar to the metal frame of an umbrella (Harris & Harris, 2001, pp. 173, 175, 177, 178). The inflorence (flowering part of the plant) is rounded with small clusters of white flowers (“University of Texas at Austin,” 2019).
A second poisonous botanical that you can find growing native in Texas is the perennial Sophora secundiflora, also known as the Mescal bean (Press, 2016, p. 6). The Mescal bean plant belongs to the Fabaceae family, also known as the pea family. This botanical is an evergreen shrub that can grow in ranges from a few feet tall to around 30 feet tall (Ladybird Johnson Wildflower Center, 2011). The leaves are of obelliptic shape which means that the distal end of the leaf is slightly larger than the proximal end and they have a rounded apex (Harris & Harris, 2001, pp. 150, 154). The leaves are also about two inches long and can be adorned with clusters of bluish-purple flowers and bright red seeds. The seeds are the part of the plant that is poisonous due to the alkaloid cytisine (sophorine) which is a highly toxic narcotic and hallucinogen. According to the Ladybird Johnson Wildflower Center, the Mescal bean plant can have blooming fragrances which are compared to artificial grape products such as grape Kool-Aid and grape bubble gum (Ladybird Johnson Wildflower Center, 2011). This fascinating bit of information makes me concerned for children who may stumble across this poisonous plant and be attracted to eating it based off of the aroma that the blooms give off. The Sophora secundiflora botanical is also part of a very important religious expression from the tribes of certain Central and Southern Plains known as the Mescal Bean Cult. These tribes included the Apache, Comanche, Delaware, Iowa, Kansa, Omaha, Oto, Osage, Pawnee, Ponca, Tonkawa, and Wichita tribes. Other synonyms used in anthropological literature include Wichita Dance, Deer Dance, Whistle Dance, and Red Medicine Society. The Tonkawa and Oto tribes have also appeared to use the mescal beans in conjunction with peyote for transitional ceremonies (Howard, 1957). Further anthropological studies are needed to further evaluate the relationships between the use of mescal beans and peyote due to the struggles of identifying the exact origins.
Lastly, we have the poisonous plant of Delphinium decorum, also known as Larkspur. The larkspur botanical is a perennial that can grow in heights from one to three feet tall (Texas A&M University, 2019). The leaves are of the palmate category which means that they are coming off from a common point, similar to the fingers on our hand and it seems that they have triplinerved leaf venation. This means that the pattern of the veins on the leaf is three-nerved where the midnerve arises from above the base and branches into two lateral nerves. The flowers of the delphinium decorum are of the raceme shape which is identified by the “…unbranched and elongated inflorescence with pedicellate flowers maturing from the bottom upwards” (Harris & Harris, 2001, pp. 156, 157, 175). According to Thomas J. Elpel, author of Botany in A Day 6th Edition, the Larkspur plant is used therapeutically for lice as a vinegar or rubbing alcohol tincture. The toxic alkaloids of the plant can be absorbed into the body by the skin so caution should be used (Elpel, 2013, p. 56). In the 19th volume of the journal Collectanea Botanica, researchers studied the properties of delphinium and found that it has at least 150 diterpenoid alkaloids. The content of the total alkaloids is highest when the plant is rapidly growing, such as in the young leaves and stem, but then declines as the delphinium ages. The toxicity levels are determined by the stages of plant growth, the part of the plant, and the environment that it is growing in. Poisoning of cattle from the larkspur plant is attributed to the norditerpenoid alkaloids. These alkaloids are the primary factor to the failure of the skeletal muscle motor unit. If death does not occur, cattle have been seen to regain composure and stand up within 24 hours of consumption (Olsen, Manners, & Pelletier, 1990).
Poisonous and toxic botanicals grow all around us and some of them can easily be mistaken for a medicinal herb that may look similar. Knowing how to properly identify botanicals if you are out in the wild is not only important for foraging, but it is also important for general safety in wildlife. Many botanicals are adorned by vibrant flowers or berries which can be especially attractive to the eyes of young children. I highly recommend that individuals check out their local wildlife or agricultural centers and see if they have available herb walks that you can attend where you can learn how to identify native botanicals in your area.
References
Boericke, W. (2005). Pocket Manual of Homoeopathic Materia Medica & Repertory: Comprising of the Characteristic and Guiding Symptoms of All Remedies (clinical and Pathogenetic [sic]) Including Indian Drugs. Patpar Ganj, Delhi, India: B. Jain Publishers.
Carlson, A. (2012, June 22). Common Water-Hemlock (Cicuta maculata) [Photograph of cicuta maculata]. Retrieved from https://www.flickr.com/photos/59003943@N00/7428795856
Culbert, D. (2013, August 20). Sophora secundiflora, the Mescalbean [Photograph of sophora secundiflora in bloom and beans]. Retrieved from https://www.flickr.com/photos/92252798@N07/9558434335
Elpel, T. J. (2013). Botany in a Day: The Patterns Method of Plant Identification: An Herbal Field Guide to Plant Families of North America (6th ed.). Pony, MO: Hops Press.
Grieve, M. (2018). Hemlock. Retrieved June 18, 2019, from https://botanical.com/botanical/mgmh/h/hemloc18.html
Harris, J. G., & Harris, M. W. (2001). Plant Identification Terminology: An Illustrated Glossary (2nd ed.). Spring Lake, UT: Spring Lake Publishing.
Howard, J. H. (1957). The Mescal Bean Cult of the Central and Southern Plains: An Ancestor of the Peyote Cult. American Anthropologist, 59(1), 75–87. doi:10.1525/aa.1957.59.1.02a00070
Kress, H. (2019). Cicuta maculata. American Hemlock. Retrieved June 18, 2019, from https://www.henriettes-herb.com/eclectic/bigelow/cicuta.html
Ladybird Johnson Wildflower Center. (2011, March 8). The University of Texas at Austin. Retrieved from https://www.wildflower.org/plants/result.php?id_plant=SOSE3
Olsen, J. D., Manners, G. D., & Pelletier, S. W. (1990). Poisonous Properties of Larkspur (Delphinium spp.). Collectanea Botanica, 19(0), 141–151. doi:10.3989/collectbot.1990.v19.122
Press, L. T. (2016). Wild Edible Plants of Texas: A Pocket Guide to the Identification, Collection, Preparation, and Use of 60 Wild Plants of the Lone Star State. Lincoln Town Press.
S. (2014, April 19). Coastal Larkspur- (Delphinium decorum)- a toxic — non-edible plant with an amazing flower endemic to CA. It is found in the Bay Area and places north. This was taken along Coulter Pine trail in the fo (14000174461) [Photograph of Delphinium decorum]. Retrieved from https://commons.wikimedia.org/wiki/File:Coastal_Larkspur-_(Delphinium_decorum)-_a_toxic_-_non-edible_plant_with_an_amazing_flower_endemic_to_CA._It_is_found_in_the_Bay_Area_and_places_north._This_was_taken_along_Coulter_Pine_trail_in_the_fo_(14000174461).jpg
Texas A&M University. (2019). Plants of Texas Rangelands » Larkspur. Retrieved June 18, 2019, from https://rangeplants.tamu.edu/plant/larkspur/
The University of Texas at Austin. (2019, March 6). Retrieved from https://www.wildflower.org/plants/result.php?id_plant=cima2
