Eulobus californicus, is a species of flowering plant in the evening primrose family known by the common name California suncup.

It is native to California, Arizona, and adjacent northwestern Mexico, where it grows in scrub, chaparral, and desert plant communities.

[1][2] Eulobus californicus is an annual herb which produces a basal rosette of leaves and then bolts a slender, erect stem which can exceed 1.5 meters in height.

[2] The upper stem is an inflorescence bearing widely spaced flowers on long pedicels.

Each flower is a cup of four bright yellow petals, sometimes with red speckles near the bases.