Photographed south of Aguila, Maricopa Co., Arizona. 19 March 2017.
ANNUAL: In the Sonoran Desert this plant develops a basal rosette of
leaves in early spring after adequate rains, then shoots up one or more
FLOWERS: Panicles of nodding flower buds. The buds open late in day to
reveal a four-petaled, white to yellow corolla, 8 stamens and a four-branched
style. By mid morning at latest the flowers close up. A
hypanthium at center of flower is reddish-brown. The yellow flowered
specimen at right was photographed at Puerto Peñ, Sonora, Mexico. March
LEAVES: The largest leaves are at ground level, are pinnately
divided/lobed and are often reddish, esp. beneath. Leaves higher on stems are
much reduced in size.
RANGE: Fairly common throughout the Sonoran Desert in Arizona and Mexico
along washes, in deep sandy soils and on rocky slopes. Absent during drought
years. Several named subspecies and varieties.
FRUIT: Pod-like, erect fruit develops below the flower, i.e. an
inferior ovary. Capsules have four chambers with two rows of seeds in each.
Onagraceae -- Evening Primrose Family