Flora of North America species comparison

Subspecies 2 (1 in the flora).

H. F. Towner (1977) found that Oenothera tubicula is self-incompatible and diurnal with opening times just prior to sunrise. It occurs primarily on limestone soil in arid lowlands, but occasionally in montane areas, from Guadalupe County, New Mexico, south to western Texas, northeast to Howard County, Texas, and south to northern Zacatecas, south-central Nuevo León, and southwestern Tamaulipas, 600–1800 m. Subspecies strigulosa (Towner) W. L. Wagner & Hoch is known only from rocky, open sites and canyons in relatively montane areas, sometimes in pine forests in southernmost Coahuila, south-central Nuevo León, and southeastern Tamaulipas, from 1500 to 2300 m. It differs in being strigillose on the ovary and distally on stems, leaves linear to narrowly lanceolate, and the petals fading red or purple.

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

Species 7 (7 in the flora).

Section Calylophus consists of 7 species (13 taxa) classified in two subsections distributed throughout the Great Plains to Arizona and south to central Mexico with a center of diversity in Texas (H. F. Towner 1977). P. H. Raven (1964) separated Calylophus from Oenothera as treated by P. A. Munz (1965) based on its peltate stigma and unusual sporogenous tissue (Towner). The peltate stigma can now be more properly interpreted as a variation from the typical Oenothera stigma, with the indusium enlarged and the lobes reduced (W. L. Wagner et al. 2007). Molecular studies (R. A. Levin et al. 2004) strongly support both the inclusion of Calylophus within Oenothera and the monophyly of the section by inclusion of a species from each of the subsections. Subsequent detailed analyses (B. Cooper, unpubl.) indicate that subsect. Salpingia is not monophyletic with subsect. Calylophus nested within it, indicating that subsections may not be justifiable as currently defined. All species, except O. serrulata, are self-incompatible and outcrossing; flowers diurnal to vespertine, opening in the early morning or from midafternoon to near sunset, wilting in one and one-half to two days; those species with diurnal flowers are pollinated by bees [especially Halictidae (halictids) and Anthophoridae (anthophorids), often oligolectic species], those with larger vespertine flowers are pollinated by hawkmoths (Towner). The self-compatible O. serrulata is autogamous and a PTH species. Recent work (M. Moore, pers. comm.) suggests that there is additional edaphic endemism within sect. Calylophus, which is being investigated using morphology and molecular analyses (B. Cooper, unpubl.), and will likely result in detection of previously unknown species in the section.

Meriolix Rafinesque ex Endlicher 1840 is a superfluous name that pertains here.

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