Taraxacum (pronounced /təˈræksəkʉm/) is a large genus of flowering plants in the family Asteraceae. They are native to Eurasia and North America, and two species, T. officinale and T. erythrospermum, are found as weeds worldwide. Both species are edible in their entirety. The common name dandelion (pronounced /ˈdændɨlaɪ.ən/ dan-di-ly-ən, from French dent-de-lion, meaning lion’s tooth) is given to members of the genus, and like other members of the Asteraceae family, they have very small flowers collected together into a composite flower head. Each single flower in a head is called a floret. Many Taraxacum species produce seeds asexually by apomixis, where the seeds are produced without pollination, resulting in offspring that are genetically identical to the parent plant.
The leaves are 5–25 cm long or longer, simple and basal, entire or lobed, forming a rosette above the central taproot. The flower heads are yellow to orange colored, and are open in the daytime but closed at night. The heads are borne singly on a hollow stem (scape) that rises 1–10 cm or more above the leaves and exudes a milky sap (latex) when broken. A rosette may produce several flowering stems at a time. The flower heads are 2–5 cm in diameter and consist entirely of ray florets. The flower heads mature into spherical “clocks” containing many single-seeded fruits called achenes. Each achene is attached to a pappus of fine hairs, which enable wind-aided dispersal over long distances.
The flower head is surrounded by bracts (sometimes mistakenly called sepals) in two series. The inner bracts are erect until the seeds mature, then flex downward to allow the seeds to disperse; the outer bracts are always reflexed downward. Some species drop the “parachute” from the achenes; the hair-like parachutes are calledpappus, and they are modified sepals. Between the pappus and the achene, there is a stalk called a beak, which elongates as the fruit matures. The beak breaks off from the achene quite easily, separating the seed from the parachute.
Dandelions are found on all continents and have been gathered since prehistory, but the varieties cultivated for consumption are mainly native to Eurasia. A perennial plant, its leaves will grow back if the taproot is left intact. To make leaves more palatable, they are often blanched to remove bitterness. Dandelion leaves and buds have been a part of traditional Sephardic, Chinese and Korean cuisine. In the north-eastern United States, dandelion is cultivated and eaten in salad. In Crete, Greece, the leaves of a variety called Mari (Μαρί), Mariaki (Μαριάκι) or Koproradiko (Κοπροράδικο) are eaten by locals, either raw or boiled in salads. Another species endemic to Crete, is eaten in the same way; it is found only at high altitudes (1000 to 1600 m.) and in fallow sites, and is called pentaramia (πενταράμια) or agrioradiko (αγριοράδικο) and which has been named Taraxacum megalorhizon by Prof. Michalis Damanakis of the Botanics Department of the University of Crete.
The flower petals, along with other ingredients, are used to make dandelion wine. The ground, roasted roots can be used as a caffeine-free dandelion coffee.
Dandelion leaves contain abundant vitamins and minerals, especially vitamins A, C and K, and are good sources of calcium, potassium, iron and manganese.
Historically, dandelion was prized for a variety of medicinal properties, and it contains a wide number of pharmacologically active compounds. Dandelion is used as folk remedies in North America, Mexico and China. Culturally, it was used to treat infections, bile and liver problems, as well as cancers, and as a diuretic. There is evidence to suggest it may have anti-inflammatory effects and assist with urinary tract infections in women. Dandelion pollen may cause allergic reactions when eaten, or adverse skin reactions in sensitive individuals. Due to its high potassium level, dandelion may also increase the risk of hyperkalemia when taken with potassium-sparing diuretics.