Taraxacum officinale, the Common Dandelion is a herbaceous perennial plant.
It can be found growing in temperate regions of the world, in lawns, on roadsides, on disturbed banks and shores of water ways, and other areas with moist soils. T. officinale is considered a weedy species, especially in lawns and along roadsides, but it is sometimes used as a medical herb and in food preparation.
As a nearly cosmopolitan weed, Dandelion is best known for its yellow flower heads, that turn into round balls of silver tufted fruits, that blow away on the wind.
Dandelions grow from generally unbranched taproots and produces one to more than ten stems that are typically 5 to 40 cm tall but sometimes up to 70 cm 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 stems can be glabrous or are sparsely covered with short hairs. The foliage is upright growing or horizontally orientated, with leaves having narrowly winged petioles or being unwinged.
The 5–45 cm long and 1–10 cm wide leaves are oblanceolate, oblong, or obovate in shape with the bases gradually narrowing to the petiole. The leaf margins are typically shallowly lobed to deeply lobed and often lacerate or toothed with sharp or dull teeth. The calyculi (the cup like bracts that hold the florets) is composed of 12 to 18 segments: each segment is reflexed and sometimes glaucous. The lanceolate shaped bractlets are in 2 series with the apices acuminate in shape. The 14 to 25 mm wide involucres are green to dark green or brownish green with the tips dark gray or purplish. The florets number 40 to over 100 per head, having corollas that are yellow or orange-yellow in color.
The fruits, which are called cypselae, range in color from olive-green or olive-brown to straw-colored to grayish, they are oblanceoloid in shape and 2 to 3 mm long with slender beaks. The fruits have 4 to 12 ribs that have sharp edges. The silky pappi, which form the parachutes, are white to silver-white in color and around 6 mm wide. Plants have milky sap 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. The fruits are mostly produced by apomixis. It blooms from March until October.
Dandelions, flowers, roots and leaves, have been used for centuries in traditional Chinese medicine & medicinal teas, most notably for liver detoxification, as a natural diuretic and for inflammation reduction. Unlike other diuretics, dandelion leaves contain good amounts of potassium, a mineral that is often lost during increased urination. There is also evidence that this property of dandelion leaves may normalize blood sugar. The roots of the Dandelion can be ground up and made into a coffee.
Dandelions are important plants for bees. Not only is their flowering used as an indicator that the honey bee season is starting, but they are also an important source of nectar and pollen early in the season. Dandelion pollen is a common allergen and is a common component in bee pollen.This allergen may be commonly responsible for asthma, allergic rhinitis, allergic conjunctivitis and contact dermatitis in sensitive individuals.
Dandelion leaves contain abundant amounts of vitamins and minerals, especially Vitamins A, C and K, and are good sources of calcium (0.19% net weight), potassium (0.4% net weight) and fair amounts of iron and manganese , higher than similar leafy greens such as spinach.
They contain 15% protein and 73% carbohydrates, 37% of which is fiber (27% of the leaves are fiber) . The leaves also contain smaller amounts of over two dozen other nutrients, and are a significant source of beta carotene (0.03% net weight), lutein and zeaxanthin (combined 0.066% net weight) .
A cup of dandelion leaves contains 112% daily recommendation of vitamin A, 32% of vitamin C, and 535% of vitamin K and 218 mg potassium, 103 mg calcium, and 1.7 mg of iron. Dandelions are also an excellent source of vitamin H, which is proven to aid in weight loss when ingested.
Other species of Dandelion
There are 232 species of dandelion currently found in Britain, and all are similar and are tricky to identify. About 40 species are endemic to Britain, and more than 100 are introduced.