(Dougl. ex Hook.) Greene
Erysimum capitatum is a species of wallflower known commonly as the sanddune wallflower, western wallflower, or prairie rocket.
This species can be found in regions across North America, from the Great Lakes to the West Coast of the United States and Alaska. Some varieties have an extremely narrow distribution, especially those endemic to California.
Erysimum capitatum is a mustard-like plant with thin, erect stems growing from a basal rosette and topped with dense bunches of variably colored flowers. Flowers are most typically bright golden, yellow, tangerine-colored, but plants in some populations may have red, white or purple flowers. Each flower has four flat petals. Seed pods are nearly parallel to the stem.
There are varieties or subspecies of this plant. Some are listed endangered species. For example Erysimum capitatum var. angustatum, the Contra Costa wallflower, is an endangered plant in the state of California. The varieties include:
- E. c. var. angustatum — Contra Costa wallflower; endemic to California, endangered species.  
- E. c. var. bealianum — Sandune wallflower; Mojave Desert, California. 
- E. c. var. capitatum — Western wallflower; flowers from May to July, widely distributed across Colorado and Utah. 
- E. c. var. lompocense — San Luis Obispo wallflower; endemic to California. 
- E. c. var. perenne (syn: Erysimum perenne) — Sanddune wallflower; endemic to California. 
- E. c. var. purshii — Pursh's wallflower; Western United States. 
Little information on this wallflower species relationship with pollinators exists. Andrew Moldenke studied a population of Erysimum capitatum var. perenne in Subalpine Talus Fell Scree of the Timberland Hall Area (2,900–3,500 metres (9,500–11,500 ft) elevation). He observed 13 species of flower visitors, although over 80% of the visits to the flowers were performed by two ant species, Formica lasioides and one from the Formica fusca group.
- Calflora: Erysimum capitatum var. angustatum
- CNPS Inventory: Endangered Plant details: Erysimum capitatum var. angustatum
- Calflora: Erysimum capitatum var. bealianum
- Utah Valley State College Herbarium
- Calflora: Erysimum capitatum var. lompocense
- Calflora: Erysimum perenne
- Calflora: Erysimum capitatum var. purshii
- Las Pilitas Nursery horticultural treatment: Erysimum capitatum, Western Wallflower . accessed 2.14.2013
- Camazine, Scott and Robert A. Bye 1980 A Study Of The Medical Ethnobotany Of The Zuni Indians of New Mexico. Journal of Ethnopharmacology 2:365-388 (p. 375)
|Wikimedia Commons has media related to Erysimum capitatum.|
- USDA Plants Profile for Erysimum capitatum
- Jepson Manual Treatment — Erysimum capitatum
- Missouriplants.com: photos and species account
- Erysimum capitatum Photo gallery