Camissoniopsis micrantha is a species of flowering plant in the evening primrose family known by the common names miniature suncup or small evening primrose.[1] This is a small, hairy annual herb producing a basal rosette of leaves. It is characterized by small yellow flowers with petals less than 5 millimeters long. The flowers dry to a reddish color as they close. This species is found in Arizona and California in the United States, along with Baja California in Mexico.[2] It grows in sandy areas in a number of habitats, from beaches to inland slopes.[3] It is the smallest member of the genus Camissoniopsis.
This species is an annual herbaceous plant that forms a basal rosette of leaves. It is covered in dense, grayish, spreading hairs. The stems are decumbent and branched or erect and simple, and are usually less than long. The dark green leaves are 1to long. The basal (on the rosette) leaves are the largest. The cauline leaves are generally shaped narrowly lanceolate, with minutely dentate (toothed) margins, and are sessile.[4]
Like other members of the genus, the inflorescence is a spike which is nodding in bud. The hairs on the inflorescence are non-glandular. The flowers have a hypanthium 1.2to long. The 4 sepals are 1to. The 4 yellow petals are 1.4to long, with up to 2 red spots near the base. The fruits are 13to long by 1.1to wide, shaped cylindric. The seeds are 0.7to large.
This species is distributed in Arizona and California in the United States, and also Baja California in Mexico. In Baja California, this species is very rare and is only found near Ojos Negros and San QuintÃn.
This species can be found growing in canyons, coastal dunes, beaches, sandy fields, and washes.