<br>Peppermint (Mentha × piperita, also known as Mentha balsamea Wild.) is a hybrid mint, a cross between watermint and spearmint. Indigenous to Europe and the Middle East, the plant is now widely spread and cultivated in many regions of the world. <br>It is occasionally found in the wild with its parent species. Although the genus Mentha comprises more than 25 species, the most common one used is peppermint. While Western peppermint is derived from Mentha piperita, <br>Chinese peppermint, or “Bohe” is derived from the fresh leaves of Mentha haplocalyx. Mentha piperita and Mentha haplocalyx are both recognized as plant sources of menthol and menthone and are among the oldest herbs used for both culinary and medicinal products. <br>It is a herbaceous rhizomatous perennial plant that grows to be 30–90 cm (12–35 in) tall, with smooth stems, square in cross section. The rhizomes are wide-spreading, fleshy, and bear fibrous roots. <br>The leaves can be 4–9 cm (1.6–3.5 in) long and 1.5–4 cm (0.59–1.57 in) broad. They are dark green with reddish veins, and they have an acute apex and coarsely toothed margins. The leaves and stems are usually slightly fuzzy. <br>The flowers are purple, 6–8 mm (0.24–0.31 in) long, with a four-lobed corolla about 5 mm (0.20 in) diameter; they are produced in whorls (verticillasters) around the stem, forming thick, blunt spikes. Flowering season lasts from mid- to late summer. The chromosome number is variable, with 2n counts of 66, 72, 84, and 120 recorded. Peppermint is a fast-growing plant; once it sprouts, it spreads very quickly.