Brassica rapa var. perviridis is a leafy vegetable cultivar group within the species Brassica rapa in the family Brassicaceae. It is most commonly known as komatsuna, or Japanese mustard spinach, and is widely cultivated in Japan and other parts of East Asia for its tender leaves and stems. The varietal name perviridis comes from Latin meaning “very green” or “deep green,” referring to the plant’s dark green foliage. Komatsuna is closely related to other cultivated forms of Brassica rapa, a species that includes turnips, napa cabbage, and various Asian leafy vegetables.

This plant is an annual leafy green with smooth, broad leaves and long edible stems that grow in a rosette form. It thrives in cool climates and can tolerate relatively low temperatures, allowing it to be grown year-round in some regions. The plant grows rapidly and is harvested while the leaves are young and tender. It is believed to have been cultivated in Japan since the Edo period, where it became associated with the Komatsugawa area of Edo (modern Tokyo), from which its common name “komatsuna” is thought to derive.

Brassica rapa var. perviridis is valued for its mild mustard-like flavor and soft texture when cooked. The leaves and stems are commonly used in Japanese cuisine in dishes such as stir-fries, soups, noodle toppings, and pickled vegetable preparations. It is often lightly sautéed, blanched, or added to broths, where it contributes both color and a subtle brassica flavor. Compared with stronger mustard greens, komatsuna has a milder taste and cooks quickly, making it suitable for a variety of home and restaurant preparations.

Nutritionally, komatsuna is rich in vitamins and minerals, particularly vitamin C, vitamin K, calcium, and beta-carotene. Like many members of the Brassicaceae family, it contains glucosinolates, sulfur-containing compounds that can break down into biologically active isothiocyanates when plant tissues are damaged. These compounds have been studied for potential antioxidant and chemoprotective properties in experimental research. The leaves also contain flavonoids and phenolic acids that contribute to the plant’s overall nutritional profile.