Toxic, poisonous, and deadly plants & fungi you should definitely know before you go out foraging

The plants & fungi outlined below are mostly relevant to the Chicago Region (although they may be relevant to other regions). I did include some comparisons of other deadly organisms not typically found in our region because they resemble organisms that are commonly found in our region. This list is not exhaustive. There are many poisonous plants & fungi out there, some of which are deadly, that aren't included here. So just because you've determined a plant or mushroom is not one that is listed below, does not mean it is safe to consume.

Knowing the poisonous plants & fungi before any other is a great way to bring confidence into the field and feel more comfortable in engaging with plants & mushrooms, because you know what species to be aware of and to respectfully give space to in the presence of their environment.

I relied heavily on my own experience but am grateful for the insights that jim mcdonald provided on plant walks I've attended with him as well as the endless insights of Sam Thayer in his wonderful books. I'm using Sam Thayer's toxicity levels below to organize the plants discussed. Inedible and mildly toxic being the least worrisome–but since they are often confused with other edible plants, are listed–and deadly, of course, being the most worrisome.

• Inedible
• Mildly Toxic
• Irritant
• Poisonous
• Highly Poisonous
• Deadly

Inedible and often confused with other plants

Invasive Honeysuckles

• Lonicera japonica, Lonicera maackii, Lonicera tatarica, Lonicera x-bella
• Note that that are also many native honeysuckles in the Lonicera genus like Yellow Honeysuckle (Lonicera reticulata) which is common in the Chicago Region

The berries are inedible and often confused with plants like Autumnberry. Autumnberry berries are not in pairs, are elliptic, and have silvery scales.

Bittersweet Nightshade

• Solanum dulcamara

According to Sam Thayer, the ripe berries are not as toxic as one might think, mostly because the plant is confused with Deadly Nightshade (Atropa belladonna), which is deadly toxic, as well as Black Nightshade (Solanum nigrum), which is another plant people mistake as poisonous but is in fact a common edible.

The main reason why you wouldn't want to eat Bittersweet Nightshade is because the taste is terrible and is therefore inedible.

That said, the leaves and green fruits of Bittersweet Nightshade are poisonous and contain a glycoside similar to atropine (one of the main toxins present in the deadly toxic Atropa belladonna).

Mildly Toxic

Buckthorn

• Common buckthorn (Rhamnus cathartica)
• Glossy buckthorn (Frangula alnus)

Berries are–as the botanical name of common buckthorn suggests–cathartic... in other words, a handful of berries will give you diarrhea

Most often mistaken for Black Cherry (Prunus serotina) or Chokecherry (Prunus virginiana)

Irritants

Poison Ivy & Poison Oak

• Poison Ivy (Toxicodendron radicans)
• Poison Oak (Toxicodendron pubescens)

Irritant that causes severe contact dermatitis, reactions vary among different people. Poison Oak tends to be confused with Fragrant Sumac (Rhus aromatica) and Poison Ivy tends to be confused with Virginia Creeper (Parthenocissus quinquefolia).

Poison Sumac

• Toxicodendron vernix

Irritant that causes severe contact dermatitis, could be confused with edible Staghorn Sumac (Rhus typhina) or Smooth Sumac (Rhus glabra). If you find yourself wandering a swamp, bog, or wetland area where shrubs are present, be aware!

Poisonous

Buckeye and Horse-Chestnut

• Aesculus spp.

The nuts, which can be confused with Chestnuts (Castanea dentata), are poisonous in high amounts. True chestnuts have simple (not compound) leaves. They also have husks with long, sharp spines.

Canada Moonseed

• Menispermum canadense

The fruit contains isoquinoline alkaloids, which can paralyze, and are often mistaken for Wild Grape (Vitis riparia).

Crown Vetch

• Securigera varia, syn. Coronilla varia

While there haven't been any documented poisonings, this is a plant to be aware of since it contains nitroglycosides and other toxins which are not toxic to ruminants but are toxic to most non-ruminants including us humans. It is commonly mistaken for true vetches (Vicia spp.) and vetchlings (Lathyrus spp.). It is also considered an invasive plant in our area.

Dogbane

• Hemp Dogbane (Apocynum cannabinum)
• Spreading Dogbane (Apocynum androsaemifolium)
• Smooth Indian Hemp (Apocynum sibiricum)

Commonly mistaken for Milkweeds (Asclepias spp.) when in the young shoot stage. At maturity Dogbanes branch while Milkweeds do not branch so they are easier to tell apart. While somewhat similar, their flowers are pretty easy to tell apart if you have a strong sense of what Milkweed flowers look like.

Typically Milkweed is not bitter, so if you are nibbling on a Milkweed shoot and it is unpleasantly bitter, it might be dogbane. As far as I know, a nibble or two won't cause significant poisoning, and the taste should deter from leading to poisoning.

Also, it's helpful to note that as far as I know, there are some poisonous milkweeds. Typically the Common Milkweed (asclepias syriaca) is eaten, and Butterfly Milkweed (Asclepias tuberosa) is used for medicine.

Iris

• Iris spp. generally, Blueflag Iris (I. versicolor)

While the specific toxins haven't been identified, the toxins are known to cause gut pain, nausea, vomiting, diarrhea, and fever. The toxins are known to be most concentrated in the root of the plant, which may be confused with other wetland plants like Cattails (Typha spp.) and Calamus (Acorus americanus).

Star of Bethlehem

• Ornithogalum umbellatum, & less frequently Ornithogalum nutans

Commonly mistaken for Alliums (wild onions and garlic), Star of Bethlehem in its fresh state is somewhat toxic, containing glycosides that cause nausea, vomiting, and abdominal cramping. Star of Bethlehem lacks the characteristic oniony scent of the Alliums it is often confused for.

Highly Poisonous

Baneberry

• White Baneberry / Doll's Eyes (Actaea pachypoda)
• Red Baneberry (Actaea rubra)

Red baneberry shoots can be mistaken for Wild Sarsaparilla (Aralia nudicaulis). The leaves before flowering can also be mistaken for Blue Cohosh (Caulophyllum thalictroides) or Black Cohosh (Actaea racemosa). And the berries of either can be mistaken for Black Cohosh just before flowering.

Toxicity may include nausea, dizziness, rapid and weak heartbeat, headache, and cognitive impairment.

Death Camas

• Anticlea elegans – rare in our region, but would likely be found in fens, Bur Oak savannas and hill prairies
• There are other genera that are considered in other regions of Turtle Island, notably of the genera Zigadenus and Toxicoscordion, but we are likely only to find Anticlea elegans in the Chicago Region.

The Death Camas group contains several similar species that were once a part of a single genus but have since been split into three closely related genera, noted above.

All parts contain toxic alkaloids, but bulbs seem to be the main issue since Death Camas is most commonly mistaken with Alliums, whose bulbs are highly sought after.

The toxic alkaloids cause a host of symptoms, the first and most notable being a burning sensation (complemented by an unpleasant flavor) that will likely prevent you from eating any further should you mistake a bulb for an allium.

False Hellebore

• Veratrum spp.

While not found in the Chicago Region, this plant occurs more frequently in the southeastern United States and strongly resembles Solomon's Seal (Polygonatum biflorum) or Solomon's Plume (Maianthemum racemosum) in the shoot stage. False Hellebore can also be mistaken for Ramps (Allium tricoccum). The species shares a similar habitat (open woods with moist soil) to the edible plants mentioned above.

The plant is rarely deadly, but is still highly poisonous, containing neurotoxic alkaloids that cause salivation, nausea, vomiting, convulsions, and heart disturbances.

Deadly

Foxglove

• Purple Foxglove (Digitalis purpurea)
• Yellow Foxglove (Digitalis grandiflora)

Most often mistaken for Comfrey (Symphytum officinale), specifically the young leaves. The plant has strong glycosides with powerful stimulant effects on cardiac muscle. It is much easier to mistake for Comfrey before flowering, as the flower spikes of Foxglove are distinctive (and beautiful!) and much different from Comfrey.

There are actually pharmaceuticals derived from or synthesized based off of Purple Foxglove with an intended effect on the heart (Digoxin). These pharmaceuticals increase the force of the heart's contractions in order to address congestive heart failure and certain kinds of arrhythmias. Of course, the dosages here are highly controlled and supervised by a qualified health professional.

Foxglove poisoning may cause nausea, vomiting, headache, diarrhea, irregular heartbeat, and convulsions. Most fatalities recorded are from medical overdoses, but also from mistaking the plant for comfrey and drank as a nourishing infusion.

The Hemlocks

Most commonly mistaken for other Apiaceae herbs, specifically Wild Carrot (Daucus carota) and Angelica (Angelica atropurpurea). Importantly all the poison hemlocks are hairless and smooth. So if you're not sure if you're looking at Poison Hemlock or Wild Carrot, ask yourself "Does the Queen Have Hairy Legs?" (Wild Carrot is also referred to as Queen Anne's Lace, and we know it's Queen Anne's Lace because of the hairs present on the surfaces of the plant). If the plant is smooth and hairless, or at least appears smooth and hairless, do not put this plant in your mouth. There are some non poisonous species in the Apiaceae family that are hairless, but you have to be absolutely certain of ID before handling, let alone ingesting.

Cicutoxin is the primarily culprit and neurotoxin in Cicuta spp. and Coniine in Conium maculatum that causes convulsions, tremors, heart disturbances, a plunge in blood pressure, delirium, coma, and respiratory paralysis. There have been many documented fatalities in both the Cicuta and Conium genus.

Common Water Hemlock (Cicuta maculata) – "Vein to the Cut, pain in the Gut!"

The phrase above helps us to remember the unique characteristic of looking at the leaves of water hemlock to positively identify: where the secondary vein branches from the mid vein to the leaf margin, the secondary veins to run straight to the "cut" or "notch" in the serrated teeth of the leaf margin rather than the tip of the margin.

Common Water Hemlock enjoys low, wet, ground in full sun or partial shade, tending to grow along the edges of ponds, marshes, and swamps, but is not considered an 'aquatic' plant in the same way Bulblet Water Hemlock is.

Bulblet Water Hemlock (Cicuta bulbifera)

Less common in the Chicago Region than Common Water Hemlock. Bulblet Water Hemlock grows in similar environments to Common Water Hemlock, but is more aquatic preferring more stable aquatic (lentic) ecosystems.

Poison Hemlock (Conium maculatum)

Apparently common in our area, but I haven't encountered it as much as I have Common Water Hemlock – still very important to be aware of as it deeply resembles Wild Carrot (Daucus carota).

Found most often in disturbed soils, as well as well-drained but rich soil in full or partial sun.

I visited a friend who showed me a garden they worked at at the University of California in Santa Cruz. The garden was beautiful and unique in that it was on a slope, holding both amazing ornamental flowers and food crop vegetables. I noted that they seemed to be growing carrot pretty sporadically compared to the organized rows of plants around them. "Oh, that's poison hemlock", she said, pulling up a specimen and pointing at the stem... "See look at the red spots!"

It honestly blew my mind that they were able to work around poison hemlock as a weed growing next to lettuces that one would find in salads and root vegetables entwined potentially with poison hemlock, but they seemed to know their way around. Either way, I finally had the opportunity to get up close and personal to distinguish between carrot and poison hemlock... a lot easier when the two are right next to each other.

Poisonous Mushrooms

Amanita spp.

• Specifically the 'Destroying Angel' Amanita bisporigera and other ghost-vibe white Amanita mushrooms in our region.

Amanita species mushrooms are gilled mushrooms easily identified in maturity by their volva (which is the remainder of a mushroom's universal veil that initially enveloped and protected the young developing mushroom, which in a mature mushroom is situated at the base of the stem often sitting halfway above and beneath the soil).

They tend to associate with oaks and other hardwoods in the summer and fall. The stem has a persistent skirt-like ring that remains into maturity, with shaggy tissue seemingly peeling off at the lower portions of the stem.

Many Amanita mushrooms contain amatoxins. Poisoning by amatoxins is extremely serious, with a fatality rate of about 50%. Symptoms tend to be delayed by about 6-24 hours after ingestion, by which time the toxins are already absorbed by the body and it may be too late.

The four stages of Amanita poisoning:

1. latency period of 6-24 hours after ingestion
   1. the toxin is actively working on the liver and kidneys, but the victim is unaware.
2. a period of about 24 hours after symptom onset
   1. violent vomiting, bloody diarrhea, severe abdominal cramps
3. another period of 24 hours about 48 hours after symptom onset
   1. victim appears to be recovering
4. relapse period
   1. liver and kidney failure leading to death

Fortunately, large doses of Milk Thistle (Silybum marianum) extract (specifically the substance silibinin found in Milk Thistle) have been utilized to neutralize amatoxins by preventing the amatoxins from reaching and damaging liver cells and help people survive amatoxin poisoning! Importantly, treatment with silibinin is most crucial in the initial 24 hour period where symptoms may be absent.

Fly Agaric (Amanita muscaria var. guessowii)

Containing a volva similar to the Amanita species describe above. This mushroom far more closely resembles the red-capped and white-warted Amanita muscaria species we are familiar with from Super Mario, the Emoji, and pop culture in general, which is because it is a variety of that exact mushroom, containing similar constituents, toxins, and effects. The main difference is that the cap of this mushroom is pale yellow to orangish yellow instead of red, still retaining the characteristic white warts that protrude from the cap.

It is often associating with hardwoods in forests with more conifers present.

While this mushroom is technically still toxic, its toxicity is different from the Amanitas mentioned above.

The toxins that prevail in Amanita muscaria var. guesowii are ibotenic acid, which is converted in the body to muscimol, a more powerfol form that passes out in the urine, as well as smaller amounts of muscarine (which can be deadly in high doses).

I'll hold off on a discussion about the psychoactive effects of this mushroom... feel free to use the internet to your desire here.

I will say that there are therapeutic qualities to this mushroom when used externally as a liniment for sciatica and nerve pain in very small doses.

I'll just leave this link here and you do what you will with it:

https://www.henriettes-herb.com/blog/fly-agaric.html

Jack-O-Lantern Mushroom

• Omphalotus illudens

Due to Jack-O-Lantern's bright orange hue, they are often mistaken for Chicken-of-the-Woods (Laetiporus cincinnatus, L. sulphureus)–which have pores and not gills–and Chanterelles (Cantharellus spp.)–which have false gills rather than true gills and do not grow in clusters on wood.

Jack-O-Lanterns tend to grow in large clusters on stumps or buried roots in the late summer and fall. They are cap and stem mushrooms with true gills.

If ingested, this mushroom is not likely to be fatal, but it will cause some serious discomfort anywhere from 20 minutes to four hours after ingestion: nausea, vomiting, cramps, and diarrhea, typically passing after the irritant is expelled.