), Raphanus sativus (common radish), Armoracia rusticana (horseradish), but also a cut-flower Matthiola (stock) and the model organism Arabidopsis thaliana (thale cress).

Pieris rapae and other butterflies of the family Pieridae are some of the best-known pests of Brassicaceae species planted as commercial crops.

Trichoplusia ni (cabbage looper) moth is also becoming increasingly problematic for crucifers due to its resistance to commonly used pest control methods.

They may have a taproot or a sometimes woody caudex that may have few or many branches, some have thin or tuberous rhizomes, or rarely develop runners.

The flowers are bisexual, star symmetrical (zygomorphic in Iberis and Teesdalia) and the ovary positioned above the other floral parts.

The filaments are slender and not fused, while the anthers consist of two pollen producing cavities, and open with longitudinal slits.

There may be one persistent style that connects the ovary to the globular or conical stigma, which is undivided or has two spreading or connivent lobes.

[5] Brassicaceae have a bisymmetrical corolla (left is mirrored by right, stem-side by out-side, but each quarter is not symmetrical), a septum dividing the fruit, lack stipules and have simple (although sometimes deeply incised) leaves.

The sister family Cleomaceae has bilateral symmetrical corollas (left is mirrored by right, but stem-side is different from out-side), stipules and mostly palmately divided leaves, and mostly no septum.

They also contain enzymes called myrosinases, that convert the glucosinolates into isothiocyanates, thiocyanates and nitriles, which are toxic to many organisms, and so help guard against herbivory.

Alfred Barton Rendle placed the family in the order Rhoeadales, while George Bentham and Joseph Dalton Hooker in their system published from 1862 to 1883, assigned it to their cohort Parietales (now the class Violales).

Early DNA-analysis showed that the Capparaceae—as defined at that moment—were paraphyletic, and it was suggested to assign the genera closest to the Brassicaceae to the Cleomaceae.

The APG III system has recently adopted this last solution, but this may change as a consensus arises on this point.

[14] Aethionemae Megacarpaeae Heliophileae Coluteocarpeae Conringieae Buniadeae Kernereae Schizopetaleae Thlaspideae Isatideae Sisymbrieae Brassiceae Thelypodieae Eutremeae Calepineae Biscutelleae Arabideae Cochlearieae Anchonieae Hesperideae Anastaticeae Dontostemoneae Chorisporeae Euclidieae Iberideae Erysimeae Lepidieae Smelowskieae Yinshanieae Descurainieae Camelinieae Boechereae Oreophytoneae Halimolobeae Physarieae Crucihimalayeae Cardamineae Alysseae As of October 2023 Plants of the World Online accepts 346 genera.

The alternative older name, Cruciferae, meaning "cross-bearing", describes the four petals of mustard flowers, which resemble a cross.

The area of origin of the family is possibly the Irano-Turanian region, where approximately 900 species occur in 150 different genera.

Two notable exceptions are exclusive self-pollination in closed flowers in Cardamine chenopodifolia, and wind pollination in Pringlea antiscorbutica.

When the cell is damaged, the myrosinases hydrolise the glucosinolates, leading to the synthesis of isothiocyanates, which are compounds toxic to most animals, fungi and bacteria.

Some insect herbivores have developed counter adaptations such as rapid absorption of the glucosinates, quick alternative breakdown into non-toxic compounds and avoiding cell damage.

Managing this pest in crops became more complicated after resistance developed against a toxin produced by Bacillus thuringiensis, which is used as a wide spectrum biological plant protection against caterpillars.

Parasitoid wasps that feed on such insect herbivores are attracted to the chemical compounds released by the plants, and thus are able to locate their prey.

The cabbage aphid (Brevicoryne brassicae) stores glucosinolates and synthesises its own myrosinases, which may deter its potential predators.

[18] Since its introduction in the 19th century, Alliaria petiolata has been shown to be extremely successful as an invasive species in temperate North America due, in part, to its secretion of allelopathic chemicals.

Research has found that removing 80% of the garlic mustard infestation plants did not lead to a particularly significant recovery of that diversity.

[28] In addition to being invasive, garlic mustard also is a threat to native North American Pieris butterflies[23][29] such as P. oleracea, as they preferentially oviposit on it, although it is toxic to their larvae.

This family includes important agricultural crops, among which many vegetables such as cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard greens, Savoy, kohlrabi, and gai lan (Brassica oleracea), turnip, napa cabbage, mizuna, bok choy and rapini (Brassica rapa), rocket salad/arugula (Eruca sativa), garden cress (Lepidium sativum), watercress (Nasturtium officinale) and radish (Raphanus) and a few spices like horseradish (Armoracia rusticana), wasabi (Eutrema japonicum), white, Indian and black mustard (Sinapis alba, Brassica juncea and B. nigra respectively).

The Brassicaceae also includes ornamentals, such as species of Aethionema, Alyssum, Arabis, Aubrieta, Aurinia, Cheiranthus, Erysimum, Hesperis, Iberis, Lobularia, Lunaria, Malcolmia, and Matthiola.

The small Eurasian weed Arabidopsis thaliana is widely used as model organism in the study of the molecular biology of flowering plants (Angiospermae).