Narrow-leaf Evening Primrose
Oenothera acutissima
NatureServe conservation status
Global (G-rank): G2
State (S-rank): S2
Utah Wildlife Action Plan status
- SGCN
External links
General information
This large, yellow, evening primrose is endemic to the Uintah mountains in Utah and Western Colorado. Oenothera acutissima occurs in seasonally moist habitats with sandy to gravelly soil between 6,000 and 8,500 feet elevation. This species has large showy flowers and capsules. It has previously been treated as a variety of O. flava; but due to this species having distinct floral morphology, odor chemistry, edaphic specialization, autapomorphic vegetative characters, and poor viability of artificial hybrids between O. acutissima and O. flava, it has been determined to be a distinct species.
Description
This large, yellow, evening primrose is endemic to the Uintah mountains in Utah and Western Colorado. Oenothera acutissima occurs in seasonally moist habitats with sandy to gravelly soil between 6,000 and 8,500 feet elevation. This species has large showy flowers and capsules. It has previously been treated as a variety of O. flava; but due to this species having distinct floral morphology, odor chemistry, edaphic specialization, autapomorphic vegetative characters, and poor viability of artificial hybrids between O. acutissima and O. flava, it has been determined to be a distinct species.
Phenology
Flowers in late May-June. Flowers open in the evening, and close by mid-morning.
Diagnostic characteristics
Oenothera acutissima is similar to O. flava, it differs by having large showy flowers with petals 2.8-5 cm long vs. 1-3 cm long.
Species range
Restricted to Moffat County, Colorado and Daggett, Uintah, and Duchesne counties, Utah; Duchesne County, UT has just one occurrence. The Center for Native Ecosystems and Colorado Native Plant Society (2006) describe the range as "in the vicinity of the Flaming Gorge National Recreation Area and around Diamond Mountain, Cold Spring Mountain, and Douglas Mountain at the eastern end of the Uinta Mountains. It has been found as far west as Burnt Mill Spring, northwest of Roosevelt, and as far east as Boone Draw, below Sand Wash Basin in Moffat County, Colorado. The Uinta Mountains are relatively isolated from other mountain environments with similar elevational characteristics, and this isolation likely sets a natural limit on the geographic distribution." Range extent is approximately 5000 - 5500 square km when calculated using GIS tools.
Taxonomy
No, this species does not have taxonomic discrepancies