Latin Binomial: Larrea Tridentata (earlier, divaricata), Caltrop family
Description: Indicator species for the Sonoran desert. “The most widespread, successful, and conspicuous xerophyte” (Jaeger, #294). Tall and rangy, wind evaporates moisture; tiny leaves, for the prevention of water loss; coated leaves to keep in moisture (but, rain washes it off, improving photosynthesis. Chemical smell especially after rains. “large, underground tuberous roots for water storage” (Idaho). Drought enduring plant (can lose up to 60-70% of its moisture?); old part dies and new clones grow surrounding it so plant lives very long time.
Habitat: Gravel to sandy substratum. Density, independent of other shrub species, due to amount of annual rainfall—closely spaced, higher rainfall; further spread out, lower rainfall. Neighbors keep their distance, which may be due to “toxic exudation from the roots” (Went, 1952).
Range: Mountain Plover may be responsible for its introduction from Argentina (Leuschner, personal communication, 4 May 2008)
Social History: Named in honor of John Anthony de Larrea, “Spanish promoter of science” (Samuel Hereman, p. 322).
1) R. J. Woodell; H.A. Mooney; and A. J. Hill, “The Behaviour of Larrea Divaricata (Creosote Bush) in Response to Rainfall in California,” Journal of Ecology 57 (March 1969): 37-44.
2) Samuel Hereman, Paxton’s Botanical Dictionary, Comprising the Names, Culture, and History of All Species, revised ed. London: Bradbury, Evans, & Co 1868.
3) Went, 1952.