Brassicaceae

The Brassicaceae, commonly known as the mustard family or crucifers, is a large family of flowering plants in the order Brassicales. It is distributed worldwide, with greatest diversity in temperate regions, and includes many herbaceous annuals and perennials, as well as a few woody forms.

Morphology and characteristics: Members typically have four-pelled, cross-shaped flowers (cruciform) with six stamens (four long and two short) and a superior ovary. The fruit is a dry capsule that splits open along both sutures, forming a siliqua or silique containing numerous seeds. Leaves are usually alternate and simple, often with a peppery taste due to glucosinolates, compounds that act in plant defense.

Systematics and notable taxa: The family includes economically important genera such as Brassica (cabbage, kale, broccoli, cauliflower, canola), Arabidopsis (A. thaliana), Raphanus (radish), Sinapis, Lepidium, Eruca (arugula), Wasabia (wasabi), and Armoracia (horseradish). Arabidopsis thaliana is widely used as a model organism in plant genetics and genomics. Phylogenetically, Brassicaceae is placed within Brassicales, with some studies recognizing a basal lineage related to Aethionema outside the core family.

Ecology and use: Many species are cultivated for food, oilseeds, condiments, or ornamentals. They are notable for glucosinolates and their hydrolysis products, which contribute to characteristic flavors and can deter herbivores. The family's global distribution and diverse life histories underpin its economic and ecological importance.