Oenothera albicaulis is an annual that grows at lower elevations in the Gila National Forest. The petals are white when fresh and the stamens are of equal length. The herbage is pubescent. Basal leaves can be either entire and oblanceolate or pinnatifid even on the same plant. With enough rain in the spring, Oenothera albicaulis can form a groundcover in wide flat canyons.

Duration: Annual

Nativity: Native

Lifeform: Forb/Herb

General: Annual herb, 5-30 cm tall, from a taproot; stems often several from the base of the plant, the central stem erect and often branching, and the lateral stems ascending or decumbent; stems white to pink, and sparsely covered with stiff hairs.

Leaves: Alternate along the stems, and also in a basal rosette which often falls off prior to flowering;  basal leaves spatulate, oblanceolate, or ovate, 5-10 cm long and 3-25 mm wide, with a smooth or toothed margin; stem leaves lanceolate to oblanceolate in outline, and usually pinnatifid into narrow lobes.

Flowers: White, showy, and opening near sunset; solitary on often nodding stalks, up to 4 cm long, from the leaf axils; hypanthium (floral tube beneath the sepals and petals) 1-4 cm long; sepals 4 per flower, 1-3 cm long; petals 4 per flower, 1-4 cm long, white and fading to pink.

Fruits: Capsule cylindric, 2-4 cm long, ribbed, and 4-chambered; splitting open along 4 suture lines to release many seeds, each 1 mm long.

Ecology: Found in dry, open sites, usually sandy flats and slopes, from 2,500-7,500 ft (762-2286 m); flowers March-July.

Distribution: AZ, east to TX and north to ND and MT, IL, NY; south to n MEX.

Notes: This is generally a small, low plant, which can appear acaulescent (lacking a stem), but most often it has well-developed true stems with leaves attached to them. Distinguished by being an annual with white stems; with showy white 4-petaled evening primrose flowers that fade to a pinkish color; and stem leaves that are long and narrow, with the edges lined with small pinnatifid lobes. There is sometimes a persistant basal rosette of larger, often less strongly toothed leaves. Distinguish from Oe. cespitosa based on the flower, which has a shorter floral tube on this species (up to 3 cm long, vs. Oe. cespitosa with a floral tube 3-6 cm long) and the fact that this species is annual while Oe. cespitosa is perennial.

Ethnobotany: Used to make a poultice or lotion to treat swellings, sore throats, and muscle strains; the fruits and seeds were added to soup or made into gravy; also the plant had extensive ceremonial uses.

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; albicaulis translates to white-stemmed.

Synonyms: None

Editor: LCrumbacher 2011, FSCoburn 2015, AHazelton 2017