Missouri is truly a place of natural beauty from its rolling Ozark hills to its blossoming native wildflowers, but it is not without its downsides. Missouri is home to poisonous mushrooms and plants, along with venomous spiders and snakes that pose a dangerous threat to humans. As the weather warms and nature starts coming to life, be on the lookout for some of the most common poisonous and venomous threats in Missouri.
Green-spored Lepiota
Green-spored lepiota may appear majestic, but they should be avoided. They are large, white mushrooms with broad caps and white gills that can turn a grayishgreen color. Their stalk is 3- to 10-inches tall with a 3- to 12-inch cap. “They look very similar to the portobello mushrooms you buy at the grocery store,” says Malissa Briggler, state botanist for the Missouri Department of Conservation.
“They are big, white, fleshy mushrooms but are terribly poisonous.” They can cause violent gastrointestinal upset, including severe vomiting and diarrhea.
These mushrooms are found in meadows in large grass areas, usually in a circular pattern called “fairy rings.”
Their seasons are summer and fall. “You will see them come up when there has been a long dry spell, then we get a lot of rain,” Malissa says. “Then, you will see them along rural roads in Missouri and in cow pastures.”
Other poisonous fungi
False morel: They look similar to edible morels but have caps that bulge outward with wrinkles rather than pitting inward with ridges.
Amanita: Many amanitas have the distinguishing feature of a fleshy ring on the stem.
Jack-o’-lantern: This mushroom is known for its bright yellow orange color, similar to that of a pumpkin.
Eastern Copperhead
The native eastern copperhead is a venomous snake with pinkish, tan, gray, or copper skin, a triangular broad-shaped head, and bands in a bow-tie shape down its body. “A lot of our other snake species that have banding patterns like that— those bands will actually be the opposite,” says Jeff Briggler, herpetologist for the Missouri Department of Conservation. “They will be narrow at the base on each side and the widest in the middle. So that’s a good characteristic that you can tell the copperhead from that pattern.”
While this snake species has mild venom and isn’t typically aggressive, it may strike if touched, startled, or stepped on. Keep an eye out for them from mid-March to early November, as they are most active during this time. The snake can be found in open forests, rocky hillsides, brushy areas along creeks, and leaf covered paths. “They like that edge effect—so if you have forest butting up against grassland,” Jeff says. “Because they do like that edge effect, they can be difficult for people to see.” They eat mice, insects, lizards, and other small prey. This is a protected species, meaning it is illegal to kill them unless they are in such close association with humans that they are likely to bite someone.
Other venomous snakes
Other venomous snakes in Missouri include the northern cottonmouth, timber rattlesnake, western pygmy rattlesnake, and eastern massasauga rattlesnake.
How do you tell the difference between venomous and nonvenomous snakes?
Venomous snakes will have:
º Vertical pupils, as opposed to round ones
º Fangs, as opposed to small rows of teeth
º A single row of scales on the underside of the tail, as opposed to two rows
º A triangular broad head, as opposed to a round head
What is the difference between poisonous and venomous?
Venomous refers to creatures that inject toxins when they bite or sting, while poisonous refers to organisms that release toxins after they have been eaten, inhaled, or absorbed through the skin.
Poison Ivy
It isn’t a surprise to most Missourians that the poison ivy plant is something they should avoid. This plant is a common woody shrub or vine, which typically grows in prairies, forests, fields, and marshes. It has three leaflets containing toxic oil. “With poison ivy, the phrase, ‘leaves of three, let it be’ is pretty catchy,” Missouri botanist Malissa says.
People can get rashes and blisters ranging from mild to severe from coming in contact with the plant. If the plant is burned, its oils can be transmitted from the smoke. “It’s all over outside in our yard or if we’re on a hike or out camping,” says Julie Weber, director of the Missouri Poison Center. “It is very important to be able to identify it because you can be exposed to it in a number of ways, by touching it or the deadly burning it—or maybe somebody even picks it, like a child can ingest it.”
The plant can be found in the spring, summer, and fall and can have different colored leaflets ranging from green to red to yellow, depending on the season. In the fall, this plant produces white waxy berries.
Another poisonous plant
Eastern poison oak: Similar to poison ivy, this plant has three leaflets. In contrast to poison ivy, both sides of all three leaflets of poison oak have distinct notches. Poison oak berries are also hairy, rather than smooth and waxy.
Brown Recluse
The brown recluse spider, known for its grayish-brown body and a violin shape on its back, is small but mighty. The spider is only about an inch long and is typically nonaggressive, yet if it were to bite, the site can ulcerate, or cause a deep wound, which can lead to damaged tissue and infection. “Sometimes a person can feel the bite and sometimes someone can’t,” Julie says. “What can happen is that it will get real red and itchy. It gets a red ring shape around it with a black dot in the middle. It can look like a bull’s-eye.”
These spiders don’t like to dine on you though. They aim for other spiders and insects, which they catch by hunting rather than catching them on a web. “As their name suggests, they’re pretty reclusive. A lot of times, as long as you’re not going to bother them, they’re not going to bother you,” says Emily Althoff, an urban entomologist for MU Extension who has researched brown recluse spiders. “They like to hide in these dark, hidden places.” They can be found in attics, basements, drawers, closets, and other crevices and also between clothing and sheets.
Another venomous spider?
Black Widow: The females are black with a red hourglass shape on their body, and the males are smaller with more of a brown coloring. Bites from this spider can be serious and cause severe pain, muscle cramps, abdominal pain, back pain, and hypertension.
What are other common threats Missouri has?
Besides venomous and poisonous threats, Missourians can also be at risk for vectorborne diseases, typically caused by ticks and mosquitoes. Ticks and mosquitoes pick up diseases by sucking the blood of infected animals, which they can then pass on to humans when they suck their blood. Some common Missouri vector-borne diseases include Lyme disease, ehrlichiosis, tularemia, Rocky Mountain spotted fever, and West Nile virus.
Anyone who has a reaction from encountering any of these threats should immediately call 911 and/or the Missouri Poison Center at 1-800-222-1222.
This article was originally published in the May 2025 issue of Missouri Life.
