Wiggins 1964, McDougall 1973, Kearney and Peebles 1961

Common Name: creosote bush Duration: Perennial Nativity: Native Lifeform: Shrub General: Aromatic, much branched evergreen shrub up to 3.5 m; with dark, glandular bands at the nodes and densely leafy toward the end of the branches. Leaves: Opposite and evergreen; each leaf consists of a pair of leaflets united at the base; leaflets are elliptical, 1 cm long, dark green, shiny, and strongly-scented (especially after rain).  Flowers: Yellow, showy, solitary on pedicels from the leaf axils; with 5 petals 7-11 mm long. Fruits: Globose capsule splitting into 5 nutlets, covered in white silky hairs. Ecology: Widespread and common on dry plains and mesas below 5,000 ft (1676 m); flowers any time after adequate rain (minimum 12 mm of precipitation) but mostly flowers February to April. Distribution: s and c CA, s UT, AZ, NM, TX; south to s MEX, and in S. Amer. Notes: The most common and widespread shrub in warm deserts of North America, ordinarily untouched by livestock; causes dermatitis in some people. Distinguished by the strong, distinct creosote scent; the paired, dark green, lustrous leaves, 1 cm long; and the yellow flowers followed by globose, white-hairy fruits. Ethnobotany: Used to treat arthritis and allergies. As a salve it is a strongly antimicrobial and a moderate sunblock. Etymology: Larrea is named for Bishop Juan Antonio Hernandez Perez de Larrea (1731-1803) in Valladolid, Spain, while tridentata means three-toothed, the appearance of the leaves being three-toothed. Synonyms: Larrea mexicana, Larrea divaricata subsp. tridentata Editor: SBuckley 2010, FSCoburn 2015, AHazelton 2015