Oenothera caespitosa is very common perennial in dry lower to middle elevation plains and hillsides. It has large white petals that turn pink with age. The anthers are large and the stigma stands well above them and is 4 parted. The leaves are crenate to lobed and gray green. The plants are acaulescent (have no stem.) Oenothera albicaulis is a very similar acaulescent plant with similar flowers, but it is an annual.
Duration: Perennial
Nativity: Native
Lifeform: Forb/Herb
General: Usually acaulescent perennial herb, to 30 cm tall, from a stout taproot; stems lacking or nearly so; plants becoming loosely colonial by spreading roots that emerge from the taproot; herbage mostly puberulent or villous-hirsute, especially on leaf margins, occasionally glabrous.
Leaves: Leaves on long petioles, emerging directly from the base of the plant to form a basal tuft; blades lanceolate to elliptic, mostly 3-30 cm long including the petiole, and 5-40 mm wide, with margins entire or more often dentate or raggedly pinnatifid.
Flowers: Large, white, showy, and fragrant, borne singly from among the leaves on a short stout pedicel up to 3 cm long; hypanthium (basal portion of the flower which contains the ovary and resembles a stalk) long and narrow, 4-14 cm long; sepals 4 per flower, 2-5 cm long, pointed downward (reflexed) at full flower; petals 4, mostly 2-5 cm long, white when fresh and turning pink or pinkish to rose-purple with age; flowers opening near or shortly after sunset and wilting the next day.
Fruits: Capsules more or less erect and forming clumps at the base of the plant, cylindric to lance-ovoid or elliptic-ovoid, mostly 2-5 cm long and up to 1 cm thick; containing numerous seeds.
Ecology: Found in a wide range of habitats, especially at open sites, from 3,000-7,500 ft (914-2286 m); flowers April-September.
Distribution: Most of western US, from TX west to CA and north to WA; also in northeastern US.
Notes: This plant is stemless for the most part above the ground. The leaves grow directly from the base of the plant in bunches (tufted, or caespitose) and are long-petioled and elliptic, with edges that are toothed and densely hairy; flowers large and white, with a long hypanthium tube which emerges from the base of the plant; later maturing into a hard, sessile fruit which is buried in the leaves. Numerous subspecies are found in the region. Oenothera albicaulis can appear similar and be nearly stemless with basal leaves, but that species is annual and Oe. cespitosa is perennial.
Ethnobotany: Used for healing, for ceremonies, as a gynecological aid, and for sores.
Etymology: Oenothera comes from the Greek oinos, wine, and therao, to seek or imbibe, alluding to the fact that the root of Oenothera biennis was used to flavor wine; cespitosa means having a densely clumped, tufted or cushion-like growth form.
Synonyms: Oenothera caespitosa
Editor: SBuckley 2010, FSCoburn 2015, AHazelton 2017
