Images source: http://www.flickr.com/photos/lynkos

A close-up view of Alyssum minus. Mustards can be distinguished from other common families in Utah by their characteristic pattern of four petals, four sepals, and six stamen.

Alyssum minus is an introduced annual of the mustard family (Brassicaceae), and a native of the Mediterranean regions of Eurasia. It is considered a weed in the United States, but the state of Utah does not list it as noxious. The plant has however spread across most of the western states including Colorado, Kansas, Montana, Nevada, Nebraska, New Mexico, California, Oregon, Wyoming and Utah (see map A). In Utah it has been observed in San Juan, Grand, Uintah, and Salt Lake Counties (see map B). The first collection in Utah was in 1944. Today it may be the most common Alyssum species found along the foothills of the Wasatch Front.

Alyssum minus is characterized by fragrant clusters of small yellow flowers appearing at the top of the plant with seeds developing lower on the stem, beneath newer blossoms. It appears at first glance to strongly resemble many members of the pea family (Fabaceae) and sunflower family (Asteraceae) including Haplopappus rydbergii, Petradoria pumila, and the groundsel speciesin particular. Upon closer inspection however, the flowers can easily be identified by the four-petal, four-sepal, and six-stamen pattern common throughout nearly all mustards.

A. minus grows very quickly in the early spring months, reaching heights of 6-12 inches by March-April and lasting through June. It is capable of adapting to almost any type of soil and has been found at altitudes stretching from sea level to 12,000ft. While fairly shade tolerant, A. minus thrives in cool, sunny environments with moderate supplies of water. It can commonly be found along roadsides and disturbed areas, in open rangeland, and along foothills.

Several names have been accumulated by Alyssum minus over the years and continents, including additional scientific nomenclatures. The currently accepted scientific name is Alyssum simplex. Common names include Field Alyssum, European Alyssum, and European Madwort.

A view of the foliage and roots of Alyssum minus. Field Alyssum can often be difficult to distinguish from other mustard species. Image source:
http://www.vanherbaryum.yyu.edu.tr/flora/famgenustur/brass/alyssum/aminu/mmic/index.htm

Map A: United States distribution

Map B: Utah distribution