Western Hooker's evening-primrose closeup

Description:

Oenothera elata var. hirsutissima (or Oenothera elata ssp. hirsutissima). Non-riparian, foothill habitat. Heavy invasion by cheatgrass.Arthur Cronquist made the combination Oenothera elata var. hirsutissima (Gray ex S. Wats.) Cronq. in 1997 (Intermountain Flora, Vol. 3A). The modern trend is towards treating plants as varieties rather than as subspecies even when separated by great distances. Most references seem to be treating this taxon as a subspecies , i.e. Oenothera elata subsp. hirsutissima (A. Gray ex S. Wats.) W. Dietr. that was published around the same time as the Cronquist publication or shortly thereafter. Why that has been adopted rather than the varietal combination is unclear. Just a few synonyms include Oenothera biennis var. hirsutissima, Oenothera elata var. hirsutissima, Oenothera hookeri subsp. hirsutissima.This species is thought to be sensitive to ozone. It is a biennial (or more rarely a short-lived perennial), the first year characterized by a basal rosette with usually long leaves, and the second year depending on the habitat becomes quite tall, commonly 6 feet (15 dm) or even much taller (reported up to 25 dm). It is one of the relatively few locally native species that will show up in expected places in suburbia along street gutters and ditches.August 8, 2009, foothills above Farmington, Davis County, Utah approx 4800 ft. elev.