Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

Home to the plants of the Sonoran, Chihuahuan and Mojave Deserts

Cirsium ochrocentrum, Yellowspine Thistle

Lepidium alyssoides, Mesa Pepperwort

Mesa Pepperwort is an attractive species with its small white showy flowers. This species closely resembles the garden cultivar Sweet Alyssum which is also in the Brassicaceae family. Lepidium alyssoides Mesa Pepperwort has 4 petals and 4 sepals, common characteristics of the Brassicaceae family which used to be called Cruciferae. A reference to the cross-like image of the 4 by 4 petals and sepals. Lepidium alyssoides Mesa Pepperwort is found in the southwestern United States in AZ, CO, UT, NM, TX.  Plants bloom from April or May to July through September and are found in elevations from: 4,000 to 9,000 feet (1,200-2,800 m) in elevations. Lepidium alyssoides Mesa Pepperwort; note in the photograph that this species has round flattened seed pods which are botanically called a silique: a silique is a type of fruit with the length being more than three times the width: when the length is less than three times the width of the dried fruit it is referred to as a silicle). Lepidium alyssoides

Scientific Name: Lepidium alyssoides
Common Name: Mesa Pepperwort

Also Called: Southern Pepperweed

Family: Brassicaceae, Mustard Family

Synonyms: (Lepidium montanum )

Status: Native

Duration: Biennial or perennial

Size: 4 to 22 inches (1-5.8 dm)

Growth Form: Forb/herb or subshrub; woody base often above ground; stems few to several from base, branched throughout; plants erect to ascending; plants without hairs (glabrous) or minutely puberulent.

Leaves: Green; having both basal and stem or cauline leaves; basal leaves not always in a rosette and not early to wither; stem (cauline) leaves arranged alternately along stem, stems leaves without stalk or sessile, lower blade leaves pinnately lobed, upper leaves linear, leaf edges or margins not toothed (entire).

Flower Color: White, flowers small, flowers in dense unbranched flowering stem (racemes), raceme stems on pedicel, ascending in flower and horizontal in fruit; petals and sepals in 4's, cross formation typical of Cruciferae family flowers; fruits are a round, flattened seed pod called a silique (note: a silique is a type of fruit with the length being more than three times the width: when the length is less than three times the width of the dried fruit it is referred to as a silicle); seeds ovate.

Flowering Season: April or May to July through September

Elevation: 4,000 to 9,000 feet (1,200-2,800 m)

Habitat Preferences: Sandstone outcroppings, dry flats, washes, canyons, river bottoms, gravelly roadsides, sand dunes, prairies, grasslands, pinyon-juniper communities and sagebrush communities.

Recorded Range: Mesa Pepperwort is found primarily in the southwestern United States in AZ, CO, UT, NM, TX. It is also native to northern and northeastern Mexico.

North America & US County Distribution Map for Lepidium alyssoides.

U.S. Weed Information: No information available.
Invasive/Noxious Weed Information: No information available
Wetland Indicator: No information available.
Threatened/Endangered Information: No information available.

Genus Information: In North America there are 47 species for Lepidium. Worldwide, The Plant List includes 234 accepted species names and a further 245 scientific names of infraspecific rank for the genus Lepidium.

The genus Lepidium was published by Carl Linnaeus in 1753.

In the Southwestern United States: Arizona has 12 species of genus, California has 22 species, Nevada and New Mexico each have 13 species, Texas has 11 species, Utah has 18 species. All data approximate and subject to revision.

There are sub-species in Lepidium alyssoides;
Lepidium alyssoides var. alyssoides, Mesa Pepperwort (AZ, CO, NM, NV, TX, UT, WI);
Lepidium alyssoides var. angustifolium, Mesa Pepperwort (NM, TX);
Lepidium alyssoides var. eastwoodiae, Mesa Pepperwort (CO, NM,UT);
Lepidium alyssoides var. junceum, Mesa Pepperwort (AZ, UT).

Comments: Mesa Pepperwort closely resembles the popular cultivated "Sweet Alyssum" which was previously included in the genus Alyssum (and a member of the Brassicaceae family); thus the species epithet "alyssoides".

Importance to Wildlife, Birds and Livestock
The seeds of Lepidium alyssoides may be foraged by ground feeding birds and small rodents.

Special Value to Native Bees, Butterflies and Insects
The flowers of Lepidium alyssoides may be visited by bees and other small insects.

The genus Lepidium (Lepid'ium:) from Greek "lepidion" which means "a little scale" a reference to the flattened shape of the fruit (seed pods).

The species epithet "alyssoides" (alysso'ides:) means "like genus Alyssum" as the little white flowers so closely resemble "Alyssum" species, also members of the Brassicaceae family.


Date Profile Completed: 03/21/2020
Kearney, Thomas H., Peebles, Robert H., 1960, Arizona Flora, University of California Press, Berkley and Los Angeles, California; as Lepidium montanum.
U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search - (accessed 03/19/2020) for Lepidium
The Plant List (2013). Version 1.1. Published on the Internet; (accessed 03/19/2020).
Ihsan A. Al-Shehbaz, John F. Gaskin, FNA; Family List |FNA Vol. 7; Brassicaceae; Lepidium; 2. Lepidium alyssoides. Flora of North America North of Mexico. 16+ vols. New York and Oxford.
L. Crumbache, 2012, A. Hazelton 2017; Editors;FNA 2010, Kearney and Peebles 1969, Heil et al. 2013, Allred and Ivey 2012; from SEINet Field Guide, on-line; - (accessed 03/17/2020).
SEINet synonyms, scientific names, geographic locations, general information.
Etymology:Michael L. Charters California Plant Names: Latin and Greek Meanings and Derivations; A Dictionary of Botanical and Biographical Etymology - (accessed 03/21/2020)