Toxicodendron rydbergii(Small ex Rydb.) Greene (redirected from: Rhus radicans var. rydbergii (Small ex Rydb.) Rehd.)
Family: Anacardiaceae
western poison ivy
[Rhus radicans var. rydbergii (Small ex Rydb.) Rehd., moreRhus radicans var. vulgaris (Michx.) DC., Rhus rydbergii Small ex Rydb., Rhus toxicodendron var. vulgaris Michx., Toxicodendron desertorum Lunell, Toxicodendron radicans var. rydbergii (Small ex Rydb.) Erskine]
PLANT: Subshrubs or shrubs spreading and rhizomatous, to 3 m tall. LEAVES: with glabrous petioles much longer than terminal leaflet, to 17 cm long; leaflets broadly obovate, 1-1.5 times as long as broad; margins crenate to serrate, 2n = 30. NOTES: Moist but often sunny sites along canyons and at seeps and springs, from the Sonoran Desert to mixed conifer forest; all AZ cos. except Pima, Pinal, Santa Cruz, and Yuma; 455-2575 m (1500-8500 ft); Apr-Jun; across s Canada and n US (e of the Cascades), s through Rocky Mountains and Great Plains to AZ, NM, and w TX.