Poison Oak
Toxicodendron diversilobum
Family: Anacardiaceae (Sumac)
Flowers — color: white, size: 1/8", type: 5 petals

The Poison Oak flower has five white to creamy petals. Plants are dioecious, have only male, with stamens, or female, with pistils. I refrained from getting close enough to distinguish.

A panicle, a multi-branching array having blooms on petioles, short stems, grows from a leaf node.

Poison Oak flower cluster under leaves Poison Oak leaves turn red in summer Poison Oak leaves of three small Poison Oak specimen oak tree supports dozens of poison oak vines Poison Oak mounded form

Habit:
Poison Oak is a deciduous perennial. It thrives in shade or sunlight with variable presentation depending on light and moisture. Small, medium or large [twelve feet] shrubs, or vines [75 feet] in shaded areas. The shiny leaves are oval or oblong and may have indentations. "Leaves of three, let it be": left and right may have at least one notch like the thumb of a mitten and are almost mirror-image; middle has two symmetric thumbs. Poison Oak remains green after annual grasses brown, but reddens before fall.

Not deadly, Poison Oak exudes oleoresin (oily, sticky) that causes allergic rashes in most humans. Branches hold the resin thru winter after the leaves are gone. Deer don't seem to be bothered moving through the forest and actually eat the stuff. The Chumash had medicinal uses for Poison Oak and may have developed immunity.