Flora of North America species comparison

Subspecies hirsutissima occurs throughout much of the western United States, but with only scattered populations in Oklahoma (Custer, Logan, and McCurtain counties) and in eastern Texas (Anderson, Brazos, and Leon counties) and western Texas (Brewster, Culberson, Jeff Davis, and Presidio counties).

Onagra spectabilis Spach is an illegitimate name as is Oenothera corymbosa Sims 1818, not Lamarck 1798, and both pertain here.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species 68 (26 in the flora).

Section Oenothera is the largest section in the genus, consisting of 68 species (79 taxa) divided into six subsections, one of which is further divided into three series. Section Oenothera has a wide geographic distribution from Canada south to Panama and throughout temperate South America, essentially encompassing the full natural distribution of the genus, although there is very sparse representation (only O. elata) from central Mexico south to Panama. Species of this section occur in a variety of habitats, often disturbed ones, from sea level to 5000 m. Most of the species are self-compatible, but with a few self-incompatible taxa and individual populations of others (W. Dietrich et al. 1997; W. L. Wagner et al. 2007). The flowers are vespertine, fading the following morning, and are pollinated by hawkmoths (in O. versicolor Lehmann perhaps by hummingbirds), or autogamous. In sect. Oenothera, as in several other sections of the genus, the diploid, bivalent-forming, usually outcrossing, species often have relatively narrow geographic and ecological ranges, whereas closely related PTH species derived from them are usually autogamous and have much wider ranges. There are 37 PTH species in sect. Oenothera, which includes the majority of species of angiosperms with this anomalous genetic system.

(Discussion copyrighted by Flora of North America; reprinted with permission.)