Western poison oak (Toxicodendron diversilobum)
Description
Toxicodendron diversilobum is extremely variable in growth habit and leaf appearance. It grows as a dense 0.5-4 m (1.6-13.1 ft) tall shrub in open sunlight, a treelike vine 10-30 feet (3.0-9.1 m) and may be more than 100 feet (30 m) long with an 8-20 cm (3.1-7.9 in) trunk, as dense thickets in shaded areas, or any form in between It reproduces by spreading rhizomes and by seeds. T. diversilobum foliage The plant is winter deciduous, so that after cold weather sets in, the stems are leafless and bear only the occasional cluster of berries. Without leaves the stems may sometimes be identified by occasional black marks where its milky sap may have oozed and dried. The leaves are divided into three (rarely 5, 7, or 9) leaflets, 3.5 to 10 centimetres (1.4 to 3.9 in) long, with scalloped, toothed, or lobed edges. They generally resemble the lobed leaves of a true oak, though tend to be more glossy. Leaves are typically bronze when first unfolding in February to March, bright green in the spring, yellow-green to reddish in the summer, and bright red or pink from late July to October. White flowers form in the spring, from March to June. If they are fertilized, they develop into greenish-white or tan berries.Botanist John Howell observed that the toxicity of T. diversilobum obscures its merits: "In spring, the ivory flowers bloom on the sunny hill or in sheltered glade, in summer its fine green leaves contrast refreshingly with dried and tawny grassland, in autumn its colors flame more brilliantly than in any other native, but one great fault, its poisonous juice, nullifies its every other virtue and renders this beautiful shrub the most disparaged of all within our region."
Taxonomic tree
-
Domain: Eukarya
-
-
Kingdom: Plantae
-
-
Phylum: Magnoliophyta
-
-
Class: Magnoliopsida
-
-
Order: Sapindales
-
-
Family: Anacardiaceae
-
-
Genus: Toxicodendron
-
-
-
-
-
-
