Common name: JACKASS-CLOVER Arizona desert: (Wislizenia refracta). Yellow. May-September. Caper family. Size: Up to 4 feet in height.
Conspicuous in late summer along roadsides and dry streambeds, the large number of yellow flowers and the widespread presence of these much branched, annual plants justify the inclusion of Jackass-clover in this booklet as one of the common flowers of the desert.
The plant ranges across the Southwest from western Texas to southern California at elevations between 1,000 and 6,500 feet. The flowers themselves are small, although the flower heads are quite conspicuous.
Since the leaves somewhat resemble the tri-foliate leaves of Clover, the plant is commonly called Jackass-clover. It is usually found in sandy locations.
YELLOW
Oenothera primiveris
O. brevipes
O. deltoides
O. cardiophylla
Common names: EVENING-PRIMROSE, SUNDROP Arizona and California deserts: (Oenothera brevipes). Yellow. March-May. Texas-New Mexico deserts: (Oenothera primiveris). Yellow. March-May. Evening-primrose family. Size: Usually low, but some up to 5 feet.
Among the commonest but most beautiful and delicate of the flowering plants of the desert are the Evening-primroses. Flowers are usually large, with the four petals either white or yellow, turning to red or pink with age. Many species are low-growing herbs with large, delicate petals; while others may be shrub-like, sometimes attaining a height of 5 feet. As the name implies, the flowers open in the evening and wilt soon after sunrise.