Beware: Poison Oak

I saw quite a bit of poison oak on Mt. Disappointment trails. Here are some hints for those who are not sure how to recognize it.

The leaves are divided into 3 leaflets, 3½ to 10 centimeters long, with scalloped, toothed, or lobed edges- generally resembling the leaves of a true oak, though the Western Poison-oak leaves will tend to be more glossy. Leaves are generally bright green in the spring (or bronze when first unfolding), yellow-green to reddish in the summer, and bright red or pink in the fall. White flowers form in the spring and, if fertilized, develop into greenish- white or tan berries.
http://en.wikipedia.org/wiki/Western_Poison-oak

Its leaves normally consist of three leaflets with the stalk of the central leaflet being longer than those of the other two; however, occasionally leaves are composed of five, seven, or nine leaflets.
Here is what the skin will look like after a contact with poison oak.
The pictures of blistered skin are as gross as it gets. If you are sensitive about things like that, do not open the links below:
http://www.heywhatsyour.com/poison-oak-blisters-on-my-hand.htm
http://www.poison-sumac.org/rash.jpg
http://www.lni.wa.gov/Safety/Research/Dermatitis/EdMat/PhytoSlides/16to20/images/Poison20Oak20leg.jpg

Some useful hints:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7431.html
http://www.scif.com/safety/safetymeeting/Article.asp?ArticleID=92

Although all the hints are self-evident but it does not hurt to check it all over again. For example,
"If you come in contact with poison oak, wash immediately or take a shower, not a bath, using strong soap or detergent."
This one is evident only when you think about it: bath might spread the poison to other parts of one's body.

Here is what it looks like:
Spring and early summer: green phase
Late summer: reddish phaseFall: yellow phase

And here is where poison oak, poison sumac and poison ivy grow:
http://www.tecnuextreme.com/plant-map.htm

Basically we should expect only poison oak here in California.

Western Poison-oak is found only on the Pacific Coast, where it is common, and ranges from Southern Canada to the Baja California peninsula.

It is one of California's most prevalent woody shrubs but also climbs, vine-like, up the sides of trees. The plant is often found in oak woodlands and Douglas-fir forests. Along the Avenue of the Giants in northern California, the vine form may be seen climbing many feet up the trunks of Coast Redwoods.

It can also be found in damp, shady areas near running water and out of direct sunlight. Any trail leading to a waterfall on California's coast will most likely be home to western poison-oak.