Mustard Family

Milk Maids © AFengler

Brassicaceae (bras-i-KAY-see-ee)

Iconic Features

  • Usually herbaceous plants
  • 4 petals form a cross
  • Fruit a pod, either silicle or silique

Description (Jepson)

  • Eudicotyledons (eudicots) – a major lineage of flowering plants including most plants traditionally described as dicots and generally characterized by
    • 2 seed leaves (dicotyledon)
    • Netted (reticulate) leaf venation
    • Flower parts in fours and fives
    • Pollen grains with 3 pores (tricolpate)
    • Vascular bundles in stem arranged in a ring
    • Taproot system
  • Annuals, herbaceous perennials, and shrubs
  • Leaves
    • Usually both basal and alternate (1 leaf at each junction with stem)
    • Generally simple (not divided into smaller units) though can be deeply cut
  • Flowers
    • Inflorescence (flower arrangement) is generally a raceme (unbranched stem with stalked flowers opening from the bottom up), arranged like a spiral staircase
    • Bisexual, generally radially-symmetrical flowers
      • 4 separate petals, usually in a cross shape
        • The old family name is Cruciferae, from the Latin for “cross-bearing”
      • Usually 6 stamens (male flower parts), 4 tall and 2 short
    • Ovary superior (above the attachment of other flower parts)
  • Fruit a capsule (a dry, multi-chambered fruit that splits open at maturity) with a translucent inner partition (septum), in 2 general types
    • Long and slender pod (silique)
    • Short and broad pod (silicle)


  • Approximately 3,780 species worldwide
    • Includes many species and cultivars of cruciferous vegetables
      • Brassica rapa – Chinese cabbage, Chinese mustard, bok choy, and turnip
      • Brassica oleracea – cabbage, broccoli, cauliflower, kale, Brussels sprout, and kohlrabi
      • Armoracia rusticana – horseradish
      • Brassica and Sinapis species – mustard condiments
  • Crushed plant tissue of most species releases peppery-smelling, pungent-tasting isothiocyanates (cyanide compounds), derived from glucosinolates (Ishida 2014)
    • Glucosinolates may be a plant defense against microbes
    • Antibacterial and antifungal properties of Mustard plants have been known since ancient times
    • Isothiocyanates are being studied as cancer therapeutics
    • Consumption of Mustard family vegetables has been shown to lower cancer risks
  • Many have a pungent, watery sap
  • Often grow, bloom, and set seed in early spring
  • Often found in disturbed soil
  • Does not form mutual relationships with mycorrhizal fungi (Hays and Watson 2019)
    • Most terrestrial plants have fungal partners, whose threadlike mycelia transfer to plant roots minerals and water from the soil, and, in return, the plants give the fungi starches and sugars created by photosynthesis
    • Because Mustard family members do not create these partnerships, mycorrhizal fungi in areas with large numbers of non-native mustards, e.g. spring mustard (Brassica rapa) and wild radish (Raphanus sativa), can die of starvation
    • The loss of the mycorrhizal fungi in soils makes it hard for plants who depend on them to compete; the soil is, in a sense sterilized (Siggs 2020)
  • Scientific name from the included genus Brassica, from the Latin word for cabbage-like vegetables
    • Alternative name Cruciferae, from the Latin for “cross-bearing,” referring to the cross pattern created by the four petals characteristic of this family and the source of the term “cruciferous vegetables”
  • Represented by 14 species at Edgewood

See General References

Specific References

Hays, Z. and D. Watson. 2019. Fungal Ecology, Diversity and Metabolites. ED-Tech Press. Pg. 128.

Ishida, M., et al. 2014. Glucosinolate metabolism, functionality and breeding for the improvement of Brassicaceae vegetables. Breeding Science 64: 48–59. J-STAGE.

Sigg, J. 2020, June 15. Nature News from Jake Sigg. Email newsletter.

Browse Some Edgewood Plants in this Family