Taraxacum officinale

Taraxacum officinale, the dandelion or common dandelion, is a flowering herbaceous perennial plant of the dandelion genus in the family Asteraceae (syn. Compositae). The common dandelion is well known for its yellow flower heads that turn into round balls of many silver-tufted fruits that disperse in the wind. These balls are usually called "clocks" in both British and American English.The name "blowball" is also used. The common dandelion grows in temperate regions of the world in areas with moist soils. It is most often considered a weed, especially in lawns and along roadsides, but the leaves, flowers, and roots are sometimes used in herbal medicine and as food.

Taraxacum officinale grows from (generally unbranched) taproots and produces several hollow, leafless flower stems that are typically 5–40 centimetres tall, but sometimes up to 70 cm (28 in) tall. The stems can be tinted purplish, they are upright or lax, and produce flower heads that are held as tall or taller than the foliage. The foliage may be upright-growing or horizontally spreading, the leaves have petioles that are either unwinged or narrowly winged. The stems can be glabrous or sparsely covered with short hairs. Plants have milky latex and the leaves are all basal, each flowering stem lacks bracts and has one single flower head. The yellow flower heads lack receptacle bracts and all the flowers, which are called florets, are ligulate and bisexual. In many lineages, fruits are mostly produced by apomixis, notwithstanding the flowers are visited by many types of insects.

Taraxacum officinale can serve as an indicator plant for soil potassium and calcium, as the plant favours soils with relatively low concentrations of calcium, but favours soils with relatively high concentrations of potassium. The dandelion is a common colonizer of disturbed habitats, both from wind blown seeds and seed germination from the seed bank. The seeds remain viable in the seed bank for many years, with one study showing germination after nine years. This species is a somewhat prolific seed producer, with 54 to 172 seeds produced per head, and a single plant can produce more than 5,000 seeds a year. It is estimated that more than 97,000,000 seeds/hectare could be produced yearly by a dense stand of dandelions. When released, the seeds can be spread by the wind up to several hundred meters from their source.

Even though dandelion pollen is of poor nutritional quality for honey bees, they readily consume it, and it can be an important source of nutritional diversity in heavily managed monocultures such as that of blueberries. Honey bees have not been shown to lower their pollination activity on nearby fruit crops when foraging on dandelions.

The plant has several culinary uses: the flowers are used to make dandelion wine, the greens are used in salads, the roots have been used to make a coffee substitute (when baked and ground into powder) and the plant was used by Native Americans as a food and medicine. T. officinale's diuretic properties - believed to be a result of the plant’s high potassium content, have been well described, with the leaves of this plant having been used for this purpose in traditional Chinese medicine for approximately 2,000 years, with other regions of the world using the plant in the same way; in French, a common name for T. officinale is pissenlit, 'a colorful description of its diuretic activity.' A study conducted in 2009 noted 'promising' results regarding these diuretic properties, but that further studies would need to be conducted into the plant's efficacy.