Oenothera suffrutescens
Syst. Bot. Monogr. 83: 214. 2007.
Illustrator:
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Herbs perennial, densely strigillose, sometimes also long-villous proximally, sometimes glabrate; from a deep, thick taproot, often with branching underground stems, or branching only at surface, these often becoming horizontal or nearly so and giving rise to new plants. Stems erect or ascending, usually many-branched, 10–120 cm. Leaves in a basal rosette (but not present at flowering) and cauline, 0.7–6.5 × 0.1–1.5 cm, blade linear to narrowly elliptic, margins entire or remotely and coarsely serrate. Flowers 4-merous, zygomorphic, opening near sunset; floral tube 4–11(–13) mm; sepals 5–9(–10) mm; petals white, fading salmon pink to scarlet-red, slightly unequal, obovate to elliptic-obovate or elliptic, 3–7(–8) mm, abruptly clawed; filaments 3–6.5(–7) mm, anthers (2.5–)3–5(–5.5) mm; style 10–22 mm, stigma exserted beyond anthers at anthesis. Capsules erect, pyramidal in distal 1/2 and abruptly constricted to terete proximal part, pyramidal part weakly or strongly angled, not conspicuously bulging at base, 4–9 × (1–)1.5–3 mm; sessile. Seeds (1–)3 or 4, light to reddish brown, 1.5–3 × 1–1.5 mm. 2n = 14, 28, 42, 56.
Phenology: Flowering Apr–Aug(–Nov).
Habitat: Sandy or clay soil, often calcareous, desert shrublands to pinyon-juniper or oak woodlands, grasslands, disturbed areas.
Elevation: 150–2000(–3000) m.
Distribution
Alta., B.C., Man., Ont., Sask., Ariz., Calif., Colo., Ill., Ind., Iowa, Kans., Mich., Minn., Mo., Mont., Nebr., Nev., N.Mex., N.Y., N.Dak., Okla., S.Dak., Tex., Utah, Wis., Wyo., Mexico (Aguascalientes, Chihuahua, Coahuila, Durango, Guanajuato, Hidalgo, Jalisco, México, Nuevo León, Oaxaca, Puebla, San Luis Potosí, Sonora, Tamaulipas, Veracruz, Zacatecas), introduced in South America (Brazil), Europe (Wales).
Discussion
Oenothera suffrutescens is naturalized sporadically in southern California (Los Angeles, San Diego, Santa Barbara, and Ventura counties; although native in eastern part of the state), Illinois, Indiana, Michigan, New York, southern Ontario, and Wisconsin.
P. H. Raven and D. P. Gregory (1972[1973]) determined Oenothera suffrutescens to be self-incompatible and polyploid. It is known to form hybrids with O. calcicola and O. hispida.
Schizocarya kunthii Spach is an illegitimate name based on Gaura epilobioides that pertains here.
Selected References
None.