Caution! There is poison ivy in the area!
Another cache along this multi-use beautiful rail trail.
Unfortunately there is poison ivy along much of this trail but with
the proper precautions we can all avoid the itch and burn.
From Wikipedia:
Toxicodendron radicans, better known as poison ivy (older
synonyms are Rhus toxicodendron and Rhus radicans), is a poisonous
North American plant that is well known for its production of
urushiol, a clear liquid compound found within the sap of the plant
that causes an itching rash in most people who touch it. The plant
is not a true ivy (Hedera).
Poison ivy can be found growing in any of the following three
forms:
as a trailing vine that is 10–25 cm tall (4 to 10
inches)
as a shrub up to 1.2 m tall (4 feet)
as a climbing vine that grows on trees or some other
support
Distribution and habitat Poison ivy grows throughout much of
North America, including the Canadian Maritime provinces, Quebec,
Ontario, Manitoba, and all U.S. states east of the Rockies, as well
as in the mountainous areas of Mexico up to around 1,500 m (4,900
ft) (caquistle or caxuistle is the Nahuatl term), and is normally
found in wooded areas, especially along edge areas. In addition to
that, it grows in exposed rocky areas and in open fields and
disturbed areas. It also grows as a forest understory plant,
although it is only somewhat shade tolerant.[1] The plant is
extremely common in suburban and exurban areas of New England, the
Mid-Atlantic, and southeastern United States. Similar species,
poison oak, and Toxicodendron rydbergii are found in western North
America. Poison ivy rarely grows at altitudes above 1,500 m (4,900
ft), although the altitude limit varies in different locations. The
plants can grow as a shrub up to about 1.2 metres (3.9 ft) tall, as
a groundcover 10–25 cm (3.9–9.8 in) high, or as a
climbing vine on various supports. Older vines on substantial
supports send out lateral branches that may at first be mistaken
for tree limbs.
It is not particularly sensitive to soil moisture, although it
does not grow in desert or arid conditions. It grows in a wide
variety of soil types, and soil pH from 6.0 (acidic) to 7.9
(moderately alkaline). It can grow in areas subject to seasonal
flooding or brackish water.
It is more common now than when Europeans first entered North
America. Real estate development adjacent to wild, undeveloped land
has engendered "edge effects," enabling poison ivy to form vast,
lush colonies in such places. It is listed as a noxious weed in the
U.S. states of Minnesota and Michigan and the Canadian province of
Ontario.
Poison ivy and its relatives are virtually unknown in
Europe.
Description
The deciduous leaves of poison ivy are trifoliate with three
almond-shaped leaflets. Leaf colour ranges from light green
(usually the younger leaves) to dark green (mature leaves), turning
bright red in fall; though other sources say leaves are reddish
when expanding, turn green through maturity, then back to red,
orange, or yellow in the fall. The leaflets of mature leaves are
somewhat shiny. The leaflets are 3 to 12 cm (1.2 to 4.7 in) long,
rarely up to 30 cm (12 in). Each leaflet has a few or no teeth
along its edge, and the leaf surface is smooth. Leaflet clusters
are alternate on the vine, and the plant has no thorns. Vines
growing on the trunk of a tree become firmly attached through
numerous aerial rootlets. The vines develop adventitious roots, or
the plant can spread from rhizomes or root crowns. The milky sap of
poison ivy darkens after exposure to the air.
Poison ivy spreads either vegetatively or sexually. Poison ivy
is dioecious; flowering occurs from May to July. The yellowish- or
greenish-white flowers are typically inconspicuous and are located
in clusters up to 8 cm (3.1 in) above the leaves. The berry-like
fruit, a drupe, mature by August to November with a grayish-white
colour.[1] Fruits are a favourite winter food of some birds and
other animals. Seeds are spread mainly by animals and remain viable
after passing through the digestive tract.
Aids to identification
The appearance of poison ivy can vary greatly between environments,
and even within a single area.
The following three characteristics are sufficient to identify
poison ivy in most situations: (a) clusters of three leaves, (b)
alternate leaf arrangement, and (c) lack of thorns. Although
several other plants fit this simplified description, any plant
that has these characteristics should be prudently avoided by
people who are inexperienced in identifying poison ivy.
Identification by experienced people is often made difficult by
leaf damage, the plant's leafless condition during winter, and
unusual growth forms due to environmental or genetic factors.
Various mnemonic rhymes describe the characteristic appearance
of poison ivy:
1."Leaves of three, let it be."
2."Hairy vine, no friend of mine." Poison ivy vines are very
poisonous.
3."Raggy rope, don't be a dope!" Poison ivy vines on trees have a
furry "raggy" appearance. This rhyme warns tree climbers to be
wary. Old, mature vines on tree trunks can be quite large and long,
with the recognizable leaves obscured among the higher foliage of
the tree.
4."One, two, three? Don't touch me."
5."Berries white, run in fright" and "Berries white, danger in
sight."
6."Longer middle stem, stay away from them." This refers to the
middle leaflet having a notably longer stem than the two side
leaflets and is a key to differentiating it from the
similar-looking Rhus aromatica - Fragrant sumac.
7."Red leaflets in the spring, it's a dangerous thing." This refers
to the red appearance that new leaflets sometimes have in the
spring. (Note that later, in the summer, the leaflets are green,
making them more difficult to distinguish from other plants, while
in autumn they can be reddish-orange.)
8."Side leaflets like mittens, will itch like the dickens." This
refers to the appearance of some, but not all, poison ivy leaves,
where each of the two side leaflets has a small notch that makes
the leaflet look like a mitten with a "thumb." (Note that this
rhyme should not be misinterpreted to mean that only the side
leaflets will cause itching, since actually all parts of the plant
can cause itching.)
9."If butterflies land there, don't put your hand there." This
refers to the fact that some butterflies land on poison ivy, since
they are not affected, which provides them protection as their
predators avoid eating the plant.
10."If it's got hair, it won't be fair." This refers to the hair
that can be on the stem and leaves of poison ivy.
Effects on the body - Urushiol-induced contact dermatitis
The reaction caused by poison ivy, urushiol-induced contact
dermatitis, is an allergic reaction. Around 15% to 30% of people
have no allergic response, but most people will become sensitized
with repeated or more concentrated exposure to urushiol. Reactions
can progress to anaphylaxis. Over 350,000 people are affected by
poison ivy annually in the US.
The pentadecylcatechols of the oleoresin within the sap of
poison-ivy and related plants causes the allergic reaction; the
plants produce a mixture of pentadecylcatechols, which collectively
is called urushiol. After injury, the sap leaks to the surface of
the plant where the urushiol becomes a blackish lacquer after
contact with oxygen.
Urushiol binds to the skin on contact, where it causes severe
itching that develops into reddish coloured inflammation or
non-coloured bumps, and then blistering. These lesions may be
treated with Calamine lotion, Burow's solution compresses or baths
to relieve discomfort, though recent studies have shown some
traditional medicines to be ineffective. Over-the-counter products
to ease itching—or simply oatmeal baths and baking
soda—are now recommended by dermatologists for the treatment
of poison ivy.
The oozing fluids released by scratching blisters do not spread the
poison. The fluid in the blisters is produced by the body and it is
not urushiol itself. The appearance of a spreading rash indicates
that some areas received more of the poison and reacted sooner than
other areas or that contamination is still occurring from contact
with objects to which the original poison was spread. The blisters
and oozing result from blood vessels that develop gaps and leak
fluid through the skin; if the skin is cooled, the vessels
constrict and leak less. If poison ivy is burned and the smoke then
inhaled, this rash will appear on the lining of the lungs, causing
extreme pain and possibly fatal respiratory difficulty. If poison
ivy is eaten, the mucus lining of the mouth and digestive tract can
be damaged. A poison ivy rash usually develops within a week of
exposure and can last anywhere from one to four weeks, depending on
severity and treatment. In rare cases, poison ivy reactions may
require hospitalization.
Urushiol oil can remain active for several years, so handling
dead leaves or vines can cause a reaction. In addition, oil
transferred from the plant to other objects (such as pet fur) can
cause the rash if it comes into contact with the skin. Clothing,
tools, and other objects that have been exposed to the oil should
be washed to prevent further transmission.
People who are sensitive to poison ivy can also experience a
similar rash from mangoes. Mangoes are in the same family
(Anacardiaceae) as poison ivy; the sap of the mango tree and skin
of mangoes has a chemical compound similar to urushiol. A related
allergenic compound is present in the raw shells of cashews.
Similar reactions have been reported occasionally from contact with
the related Fragrant Sumac (Rhus aromatica) or Japanese lacquer
tree.
Happy caching!
This cache has been placed by a Central Ontario
Geocacher!
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