Killer grass

It is believed that the previous two years of drought contributed to Tifton 85 grass producing cyanide gas that killed some cattle near Austin, Texas. Tifton 85 is a 1992 hybrid of Bermuda grass (Tifton 68 from Tifton, Georgia, US) and a South African grass, grown for its cold tolerance, high protein and digestibility.

The cattle died of prussic acid ( cyanide poisoning )

Cyanogenic glycosides in plants yield free hydrocyanic acid (HCN) aka prussic acid when plants are damaged.

Young plants and leaves of older plants contain dhurrin which can break down to release cyanide gas. This tends to be highest in young rapidly growing plants, especially those stunted by drought or damaged frost or other mechanical means. Heavy fertilizing with nitrogen in areas low in phosphorus is more likely to produce the gas. Treatment with 2,4-Dichlorophenoxyacetic Acid ( a broad leaf herbicide and pesticide ) also increases the risk.

It does decrease as plants die, decreasing slowest in drought stricken plants. The remaining acid may be concentrated in new shoots when regrowth begins. The darker the leaves, the higher the concentration.

Plants that can produce cyanide include: Apple, Apricot, Cherry, Peach, Elderberry, Flax, various sorghums, various grasses, hydrangea, lima bean, and others.

Tifton 85 Grass
Cyanide-Producing Grass Linked to Texas Cattle Deaths
Sorgums, sundangrasses for forage
effect of 2,4-Dichlorophenoxyacetic Acid on Edogenous Cyanide, ($)

The toxins in the plant

So what is it that makes one plant poison and another food? It is the chemical compounds in the plant. Some poisonous plants have several of these toxins, some only one.

This is a large group of nitrogen compounds and the most common of plant toxins. Over 20% of plants contain an alkaloids. Mixed with salts they form medicines or poisons. They usually have a bitter taste. One of the first clues a plant might be toxic is taste. Any unknown plant with a bitter taste should be suspect.
Alkaloids are often the hallucinogenic compound in a plant.
(jimson weed, angel’s trumpet, henbane, deadly nightshade, mandrake)
Plant poisoning alkaloids

These are converted to sugar and non-sugar compounds by hydrolysis. The non-sugar part contains the toxin. Often used as heart or stomach medicine, in the wrong dose they kill. They block ATP production, which prevents you from making energy, causing rapid death.
( digitalis, olenander, lily of the valley, squill, bamboo, elderberry )
Plant Poisoning Glycosides

Oxalates are carbon based acids that are corrosive. They form tiny crystals that cause damage when ingested. The pain is usually strong enough that people do not continue to eat the plant. Often plants containing oxalates have heart shaped leaves that tend to be large.
( philodendron, dumb cane, rhubarb, taros, agaves )
Oxalates: Adverse drug of the month

These only occur rarely in plants, but are the most powerful of all the toxins. They are currently being researched for their anti-fungal abilities.
( rosary beans, castor beans, some latex )
Peas and beans gone bad

Nitrogen compounds. These cause degeneration of motor tract, leading to paralysis and death.
( sweet peas, mistletoe, poison vetches )

Cause cellular degeneration of internal organs such as livers.
( deathcap mushrooms )

Resins and resinoids
Sap that hardens into a hard glossy material.
(poison ivy, milkweed, rhodendron, mountain laurel, some pines )

Mineral toxins
Some plants uptake toxins from the soil
( poison vetches )

Alcohol is common in plants, but rarely toxic. When it is toxic it is extremely toxic. There are two main alcohol toxins: cicutoxins and oenanthotoxins found in water hemlocks that cause seizures. The second contains tremetones found in plants like snake root.
( water hemlock, white snake root )

This causes skin irritations and itching. It is the liquid of the plant that causes the problem.
( poison ivy, poison oak )

Toxic Plants

One of the first things I noticed as a gardener down here was that every plant had thorns, or was toxic or both. It’s a harsh environment.

A few months back I had the pleasure of attending ‘Murderous Plants and Poisonous Herbs’ talk given by Barney Lipscomb. If you have a chance to see it, don’t miss the talk.

It started me thinking more about what makes a plant toxic and which plants are toxic. So I’ll be digging into all sorts of cool information about toxicity, plants, and poison for a bit. I’ve a huge stack of books on toxic plants piled on my desk and a longer list of websites to dig through. Homeland Security should be showing up any day now. I’ll try to get these written before they come take me away.

Unintentional death by poison happens to about 8 people per 100,000 per year. In 2005 23,618 people were died from accidental poison. While that does not sound like much, poisoning death rates have doubled from 1985-2004. Death by poison is second only motor vehicle deaths in accidental death totals nationwide.

Accidental death by poison mostly occurs in people 15 to 65 years of age. If you are between 34-53 you are more likely to die by poison then in a motor vehicle wreck.

As with any substance, ‘The dose makes the poison’. Water can kill you if there is enough of it to prevent you from breathing, or if you drink enough to upset your body chemistry.

Toxic doses are measured in LD 50, which refers to the dose will kill 50% of the healthy adults who are exposed to it. ( LD Lethal Dose )

Somewhere around 700 known toxic plants grow in the United States.

Should you ever need immediate help or have a question about a poison, call 1-800-222-1222. If you have come into contact with a substance you are not sure about, keep some handy for identification or at the very least take a photo. Treatment depends on proper identification.

How do accidental poisons happen? Most of them occur in hospitals when the wrong medicine or dose is given to a patient. In the world outside it is from misidentified plants. Know your plants. Google image search is great for finding plant names. But use a trust but verify method. I’ve seen many misnamed on the web. Find your plant, then verify, it is the correct name for the plant using another source.

More information:
Common Poisonous Plants
SciAm: Strange but true: Drinking too much water can kill

Most common plants involved in poisonings

The most common cause of poison by plant is misidentification of the plant.

Common toxic plants
Ilex sp. ( Holly )
Phytolacca americana ( Pokeweed )
Epipremnum aureum ( Poison Ivy )
Rhododendron sp. ( Azalea and Rhododendron )
Taxus sp. ( Yew )
Eucalyptus sp. ( Eucalyptus )
Pyracantha sp. ( Pyracantha )
Hedera helix
Solanum dulcamara
Philodendron ( Philodendron )
Capsicum annuum ( pepper )
Dieffenbachia ( dumb cane )
Euphorbia pulcherrima ( Poinsettia )
Spathiphyllum ( Peace lily ) Crassula ( Jade )
Toxicodendron radicans ( Pothos aka Devil’s Ivy )
Schefflera actinophylia ( Umbrella tree )
Saintpaulia sp. ( African violet )
Chlorophytum comosum ( Spider Plant )
Schlumbergera bridgesii ( Christmas Cactus )
Hedera helix ( English Ivy )

See also:
Toxic Tales, Poison Information and Toxicology Facts

Shrooms and fungus

I recently attended a talk by Sherri Angels on mushrooms. The most important message of the talk was ‘Phds in mushrooms buy them at the local grocer they don’t pick them and eat what they find. Ever.’ Why? Because there is not a whole lot of difference between toxic and not toxic mushrooms and even experts guess wrong sometimes. The mushrooms at the grocers are factory grown.

What happens if you eat a toxic mushroom? Well in 4 hours you’ll need a liver transplant, In 6 hours the first symptoms will show up.

Mushrooms all have a cap, gills, stem and some have a volva and or ring. The cap, gills and stem I’m sure you can identify. The ring (aka annulus ) is on the stem and can help you to id a mushroom. The cups ( aka volvas ) is a cup like ring around the base of the mushroom. This might be above ground and visible or below ground and not visible with out digging up the mushroom. Most mushrooms (95%) with a ring and or cup are toxic. This does not mean the absence of a ring and cup makes a mushroom safe to eat.

Other than color, size and the presence or absence of a ring or cup the color of the spores varies and can help id a mushroom. To see the color of the spores you’ll need paper that is part black and part white. Remove the cap and gently press the cap, gill side down on to the paper and wait an hour or so. The color spores you think you see looking at the mushroom are not always what will appear on your paper.

In general and there are exceptions, blue mushrooms are your hallucinogens. Some like, Lactarius remain blue even when cooked. It has a milk that leaks out when the mushroom is cut that is also blue. These mushrooms can commonly be found in Mexico for sale. You should be able to find it in the woods here or anywhere besides the west coast in the US.

Jack O Lantern mushrooms are orange and have gills that glow green in the dark. They are only found in the fall. Because this one so closely resembles the non toxic Chanterelles it is responsible for many mushroom poisonings each year. This one is generally found anywhere east of the rockies.

Corn smut fungus ( Ustilago maydis ) grows on sweet ears of corn. It ruins the corn, but many consider the mushroom a delicacy. In Mexico it is used to add a smoky flavor to many foods. You might find it in canned form at your local Mexican grocery store.

The bright yellow slimy mold that shows up in your garden after a rain here is Fuligo septica. It’s here to stay, if you have it there not much you can do. It does vanish once things dry out. If you are really desperate I would think a fungicide would help at least temporarily. It is actually a plasmodium. All protoplasm, no cells. I understand it can be cooked and eaten like scrambled eggs but I don’t recommend doing so.

If you want to forecast the weather with mushrooms look for an earthstar ( Astraeus hugrometricus ). It is star shaped and often found at the base of pines and other trees in sandy soil. The legs of the star close up around the mushroom in dry weather and unfold in damp weather. There are many varieties of this mushroom throughout the US. The spores of this mushroom can be toxic in high doses. So should you find one and bring it home to play with, use a bit of caution.

The shelf like fungi you see growing on dead trees that looks like a seashell is Bracket fungi, aka shelf fungi.

Lichens are symbiosis between a fungus and an algae or bacteria. Some of the more commons ones you’ll see are: Trichoderma which causes green mold and kills other fungi; Aspergillus which is a human and plant pathogen and causes fruit rot; and Penicillium which gives your blue cheese its flavor and can be converted to penicillin.

As far as the mushrooms you eat, wash them thoroughly and store them in paper bags to keep fresh. When buying mushrooms look for tight, closed caps and don’t buy any slimy mushrooms. The slime is caused by bacteria.

More information:
7 Glow in the Dark Mushrooms Species Discovered

While fact checking this entry I ran across Tom Volk’s Fungus of the Month pages. If you want to know more that’s a fun place to start. And Lichens of North America has a great photographic collection of lichens if you need help id’ing a lichen.

Extreme close up photos of slime molds

Toxic house plants

An awful lot of people come here and look for information on poison plants. I can’t tell if they are looking to do in a significant other or if they have become paranoid about the plants talking and are concerned the plants will try to do them in? ( Have you been taking good care of your houseplants? )

I’ve only had one problem with pets and houseplants. I had a lab who ate every house plant I brought home. Then he ate a 1 foot tall very spiny cactus. It was the last houseplant he ate. He was fine in a day or two. ( Only a lab wouldn’t stop after the first bite of spines and cactus. )

The reason I haven’t covered toxic plants in detail is because there is a great deal of conflicting information on the net about which plants are toxic. So I hesitate to give out information that may be inaccurate. When in doubt the Extension Office or .edu website is far more likely to have correct information than a .com/.org/.net website.

And, of course, don’t eat your houseplants.

More info:
Houseplants: Safe and Poisonous Varieties
FDA Poisonous Plant Database

Invasive plants murder neighbors by poison

If it wasn’t bad enough that your plants were talking about you, now the little devils are poisoning each other.

…Scientists at the University of Delaware have uncovered a hidden weapon that one of the most invasive wetland plants in the United States uses to silently and efficiently bump off its neighbors.

The invasive strain of Phragmites australis, or common reed, believed to have originated in Eurasia, exudes from its roots an acid so toxic that the substance literally disintegrates the structural protein in the roots of neighboring plants, thus toppling the competition.

Phragmites is taking over the marsh world, said UD plant biologist Harsh Bais. It’s a horticultural disaster. . . .

[ read more UD plant biologists uncover top wetland plant’s hidden weapon ]

See also:
Plants have a social life too