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evening primrose

Habit Herbs strigillose, usually also villous, with appressed or spreading hairs, sometimes these with red-pustulate bases, distally sometimes also glandular puberulent. Herbs (annual or perennial), [shrubs].
Leaves

alternate or basal;

stipules absent.

Flowers

buds green to yellowish green, red-striped, or sometimes red throughout, with free tips 2–7 mm;

petals 30–47(–55) mm;

anthers 8–15(–22) mm.

usually actinomorphic, rarely slightly zygomorphic (in Oenothera), (3 or)4-merous;

stamens 2 times as many, or rarely as many, as sepals;

pollen usually shed in monads, rarely tetrads (Chylismia sect. Lignothera).

Fruit

a dry capsule, usually dehiscent, sometimes indehiscent.

Seeds

few to numerous, without hairs or wings, [very rarely with asymmetrical dry wing (Xylonagra)], or with dry (Oenothera), erose or smooth wing, or with thick, papillate wings (Chylismiella).

2n

= 14.

Oenothera elata subsp. hirsutissima

Onagraceae tribe Onagreae

Phenology Flowering (Apr–)Jul–Sep(–Oct).
Habitat Montane sites along streams, mesic meadows, roadsides, near permanent or seasonally wet sites, ditch banks, riverbanks, flood plains, fallow agricultural land.
Elevation 10–3000 m. (0–9800 ft.)
Distribution
from FNA
AZ; CA; CO; ID; KS; NM; NV; OK; OR; TX; UT; WA; Mexico (n Baja California, Chihuahua, Coahuila, Durango, Sinaloa, Sonora)
[BONAP county map]
North America; Mexico; Central America; South America; West Indies
Discussion

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.)

Genera 13, species 265 (12 genera, 199 species in the flora).

Onagreae account for more than half the total genera in Onagraceae and diversified from a center in southwestern North America (L. Katinas et al. 2004). Delimitation of the tribe by W. L. Wagner et al. (2007) differs from previous ones by the exclusion of Gongylocarpus, now in its own tribe, by the segregation of eight genera (Camissoniopsis, Chylismia, Chylismiella, Eremothera, Eulobus, Neoholmgrenia, Taraxia, and Tetrapteron) from Camissonia, and by the inclusion of three previously separate genera (Calylophus, Gaura, and Stenosiphon) in Oenothera. Within the branch of the family that lacks stipules (Gongylocarpeae, Epilobieae, and Onagreae), the last two tribes form a clade that has very strong molecular support (R. A. Levin et al. 2003, 2004), but no obvious morphological synapomorphy. The clade may be defined by a cytogenetic change from the base chromosome number of x = 11 found in Circaeeae, Gongylocarpeae, and Lopezieae, to x = 18 in Epilobieae, and x = 7 in Onagreae; however, these changes could also have occurred independently. Other than the new chromosome number x = 7, the only apparent morphological synapomorphy for Onagreae alone is pollen with prominent apertural protrusions (J. Praglowski et al. 1987, 1989), a character state also found in Circaeeae (Praglowski et al. 1994). The monophyly of Onagreae has moderate (Levin et al. 2004) to strong support (V. S. Ford and L. D. Gottlieb 2007).

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

Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Oenothera > Oenothera elata Onagraceae > subfam. Onagroideae
Sibling taxa
O. elata subsp. hookeri
Subordinate taxa
Synonyms O. biennis var. hirsutissima, O. elata var. hirsutissima, O. elata subsp. texensis, O. grisea, O. hewettii, O. hirsutissima, O. hookeri subsp. angustifolia, O. hookeri var. angustifolia, O. hookeri subsp. grisea, O. hookeri var. grisea, O. hookeri subsp. hewettii, O. hookeri var. hewettii, O. hookeri subsp. hirsutissima, O. hookeri var. hirsutissima, O. hookeri var. irrigua, O. hookeri subsp. ornata, O. hookeri var. ornata, O. hookeri var. semiglabra, O. hookeri var. simsiana, O. hookeri subsp. venusta, O. hookeri var. venusta, O. irrigua, O. jepsonii, O. macbrideae, O. ornata, O. simsiana, O. venusta, O. venusta var. grisea, Onagra macbrideae, O. ornata
Name authority (A. Gray ex S. Watson) W. Dietrich: Ann. Missouri Bot. Gard. 70: 195. (1983) Dumortier: Fl. Belg., 89. (1827)
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