Poisonous Plants

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Poisonous Plants

• Derek Tilley
• Plant Scientist
• USDA-NRCS
• Plant Materials Center
• Aberdeen, ID

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• Many poisonous plants or animals have harmless
  look-alikes
• Monarch and Viceroy

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Coral snake and Scarlet King snake
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Poison Ivy

• Leaves in 3s
• Leaves have a thumb
• Often a vine
• White berries

• Turns red in fall

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Look-Alikes?
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• Shady areas, canyons,
• AZ to Canada to East Coast

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Poison Oak
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• 3 lobed leaves
• Woody shrub or vine
• Glossy leaves
• Red in fall
• Foothills from Baja to B.C.

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Poison Sumac

• Woody shrub or small tree
• Red in fall
• Eastern states

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Poison Ivy, Poison Oak and Poison Sumac

• Toxins in oils
• Anything touched is contagious
• Oils are broken down by soap
• Wash before oil dries (10 to 20 minutes max.)
• Wash hands
• Wash clothing, shoes
• Do not burn! Oil travels in smoke
• Can not spread from blisters
• Treat with Calamine Lotion

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Poison Hemlock and Water Hemlock
The suicide of Socrates 399 BC, Athens.
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Poison Hemlock
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Poison Hemlock
Symptoms
Description

• Tremors
• Loss of muscle control
• Seizures
• Salivation
• Dilated pupils
• Sweating
• Ascending paralysis
• Death

• Parsley or carrot-like leaves
• Clusters of small white flowers
• Reddish dots on stems
• Common in ditches, streams and even backyards in
  Idaho, Utah and other states

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Water hemlock
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Water Hemlock
Description
Symptoms

• Nausea
• Abdominal pain
• Tremor
• seizures

• Clusters of small white flowers
• Cross section of root shows chambers
• Found in mountain streams, springs, ditches and
  ponds throughout N. America

A single bite of the root, which contains the
highest concentration of toxin, has been reported
to kill an adult!
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Giant Hogweed
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Giant Hogweed
Description
Symptoms

• Plants exude clear watery sap
• Sensitizes skin to ultraviolet radiation
• Sap sun infection, blisters and scarring

• 10 to 20 feet tall
• Clusters of small white flowers
• Large leaves
• Introduced weed found currently in Washington
  State and the northeast. May be moving to ID
  Panhandle.

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QUIZ
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Death Camas
Sego Lily
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Death Camas
Description
Symptoms

• Nausea
• burning of mouth and throat
• Salivation
• muscular weakness
• Vomiting
• Diarrhea
• death
•  

• Many small cream to yellow flowers
• Grass or lily-like leaves
• Valleys and foothills in western states

Often mistaken for sego lily by tuber hunters
and scouts
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Common House Plants
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Oleander
Symptoms

• Nausea
• Vomiting
• Accelerated or slowed heartbeat
• Heart failure

All parts are very poisonous. One leaf is enough
to cause death
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Morning Glory

• Symptoms
• Drowsiness
• Nausea
• Vomiting
• Diarrhea
• Numbness of extremities
• Muscle tightness
• Hallucinations

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Dumbcane

• Painful and immediate swelling of the mouth and
  throat occurs after chewing on dumbcane.
• Speech impediment can occur, sometimes lasting
  for several days.
• Avoid eye contact with the juices which can
  result in intense pain and swelling.

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YEW
Symptoms

• Nausea
• Vomiting
• Increased salivation
• Stomachache
• Diarrhea
• Sleepiness
• Shortage of breath
• Trembling
• Spasms
• Malfunction of the heart which leads to collapse
  and death

All parts of the plant are poisonous. Reported
poisonings caused by the usage of yew utensils.
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Rhubarb
During World War I rhubarb leaves were
recommended as a substitute for other veggies
that the war made unavailable. Apparently there
were cases of acute poisoning and even some
deaths. Some animals, including goats and swine,
have also been poisoned by ingesting the leaves.
Symptoms difficulty breathing burning in the
throat abdominal pain, nausea, vomiting,
diarrhea Convulsions, coma death from
cardiovascular collapse
From an MSDS (Material Safety Data Sheet) for
Oxalic acid, LD50 in rats is 375 mg/kg. So for a
person about 145 pounds that's about 25 grams of
pure oxalic acid required to cause death. Rhubarb
leaves are probably around 0.5 oxalic acid, so
that you would need to eat quite a large serving
of leaves, like 11 lbs, to get that 24 grams of
oxalic acid. Note it will only require a
fraction of that to cause sickness.
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Symptoms excess salivation, colic, vomiting,
diarrhea and dehydration, develop several hours
after ingestion.  Body temperature may rise to
104 F. Hyperexcitability and convulsive
seizures are seen before death. 
Rosary Pea
Toxins are released only if the seed is chewed
and swallowed.  As little as 0.00015 body weight
will cause fatality in humans. 
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Poinsettia???
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MUSHROOMS
Symptoms

• Feeling sick
• Stomach cramps
• Vomiting
• Watery or bloody diarrhea
• Liver failure
• Death

Symptoms may show up immediately, or may appear
several hours later. Often when symptoms finally
occur, liver damage is irreversible.
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Edible Wild Plants

• Almost all have a poisonous look-alike relative
• Most need to be boiled or soaked or roasted to
  get out toxins
• Acorns, elderberry, cactus, thistle and many
  others

So what plants are safe to eat?
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