WILDFLOWERS OF NEW MEXICO

Leafy, nearly hairless stems sprawl across the ground, occasionally erect; the dense mat of basal leaves can reach 16-inches across. Note the erect buds, large, showy, white flowers with notched or heart-shaped petals, and a hairy throat. Flowers open in the evening for moth pollination and fade the next day.

FLOWERS: April–September. Erect floral tubes 1 1/2–5 1/2-inches long (4–14 cm) sprout from the leaf axils; buds erect, hairy, with red stripes and pointed with tiny, closed (not spreading) tips; 4 white petals 3/4–1 3/4-inches long (2–4.5 cm), heart-shaped, throat hairy; stamens unequal, stigma with 4 slender, cross-shaped lobes. Fruit a strongly ribbed capsule 5/8–2 3/8-inches long (1.5–6 cm); note the tiny bumps or tubercles that line the ridges (use lens).

LEAVES: Basal rosette and alternate stem leaves. Blade shape variable on same plant, 3/4–10 inches long (2–25 cm), elliptic, hairy, margins entire or with irregular teeth or shallow to deep lobes along midrib.

HABITAT: Sandy, gravelly soils, roadsides; desert grasslands and scrub, pinyon-juniper, ponderosa/yellow pine, spruce-aspen forests.

ELEVATION: 4,300–8,500 feet.

RANGE: Widespread in all states from Rocky Mountains westward.

SIMILAR SPECIES: 35 species of Oenothera in NM, some restricted to one or a few counties, with 7 white evening primrose species. O. caespitosa has 4 subspecies varying from hairless to densely hairy. One other sprawling to occasionally erect species, Prairie Evening Primrose, O. albicaulis, statewide, has nodding buds.

NM COUNTIES: Statewide, except for eastern and southern border counties, in low- to mid-elevation, arid habitats: Bernalillo, Catron, Chaves, Cibola, Colfax, Dona Ana, Grant, Hidalgo, Lincoln, Los Alamos, McKinley, Mora, Rio Arriba, Roosevelt, San Juan, San Miguel, Sandoval, Santa Fe, Sierra, Socorro, Taos, Torrance, Union, Valencia.