This is definitely the most important plant to be learnt by any resident or visitor to Monterey County. It has leaves in threes, shiny and bright green, but turning to brilliant red in the fall. Flowers are dioecious, male and female flowers growing on separate plants. Poison Oak can grow as a creeper, climber or as an ordinary shrub. All parts of the plant secrete an oily resin (urushiol), which is capable of causing an extremely unpleasant rash. The oil can affect you by direct contact, or from clothes that have been in contact with the plant, or even from dogs. Inhaling smoke from burning Poison Oak can also induce a reaction. There is a popular saying, inaccurate but worth remembering — “Leaves of three, let it be”.