Toxicodendron diversilobum (Poison Oak)

5/19/17 William Heise County Park, Laguna Mountains, San Diego County, CA 

5/19/17 William Heise County Park, Laguna Mountains, San Diego County, CA

3/24/19 Trans Preserve Trail, Santa Rosa Plateau Ecological Reserve, 

Murrieta, SW Riverside County, CA 

3/23/02 Trans Preserve Trail, Santa Rosa Plateau Ecological Reserve, Riverside County, CA

LIFE LIST NOTES:

COMMON NAME: Poison Oak

SPECIES: Toxicodendron diversilobum

FAMILY: Anacardiaceae (Sumac Family)

LIFE LIST DATE: 3/23/2002

LOCATION: Trans Preserve Trail, Santa Rosa Plateau Ecological Reserve, Riverside County, CA

*******************************************************************************

Treatment from The Jepson Manual (1993):

Shrub (sometimes tree-like) 0.5–4 m or vine < 25 m

Stem: twigs glabrous to sparsely hairy, gray- to red-brown

Leaf: petiole 1–10 cm; leaflets generally 3(5), ± round to oblong, thin to ± leathery, becoming bright red in autumn, base truncate to rounded, tip obtuse to rounded, margin entire, wavy, or slightly lobed, upper surface glabrous, ± shiny, lower sparsely short-hairy; terminal leaflet 1–13 cm, 1–8 cm wide; lateral leaflets 1–7 cm, 1–6 cm wide

Inflorescence drooping, spreading, or erect; pedicels 2–8 mm; bractlets < 1 mm

Flower: sepals, petals generally ovate, yellow-green

Fruit 1.5–6 mm diam, spheric to slightly compressed, becoming leathery, glabrous to finely bristly, creamy white; pulp white, black-striate

Ecology: Canyons, slopes, chaparral, oak woodland

Elevation: < 1650 m.

Bioregional distribution: California Floristic Province, sw edge Mojave Desert

Distribution outside California: to British Columbia, Baja California

Flowering time: Apr–May