WESTERN WALLFLOWER (ERISEMUM CAPITATUM)
A member of the Mustard family (Cruciferae), this plant can reach 32" tall, with grayish-green, lance-shaped, tooth-margined leaves forming a basal rosette, to 5" long (Epple, main Wildflower page, p.79). Stem leaves are narrow, with small teeth.
The flowers, which may bloom from March to September, are bright yellow, with 4 petals, forming in a cluster on a "rounded, terminal raceme" (ibid.); the bloom is followed by a very slender, erect 4-sided pod up to 4" long. All of these images were taken in March of 2005, in various parts of Hot Springs Canyon.
Here below is a closer view of the flowers: (click on the image to enlarge it.)
Here below is a close-up of the leaves: (click on the image to enlarge it.)