Product Code Database
Taraxacum officinale, the dandelion or common dandelion, is a herbaceous perennial flowering plant in the daisy family, Asteraceae. The common dandelion is well-known for its yellow that turn into round balls of many silver-tufted fruit, which Wind dispersal. These balls are sometimes called "clocks" or "blowballs".
Originally native to Eurasia, as a result of its hardiness and easy propagation, the dandelion has become widely established across several continents. It has been introduced to southern Africa, the Americas, Australia, and New Zealand. It grows in temperate regions of the world in areas with moist soils. They are able to grow in a variety of environments and are tolerant of crowding, extreme temperatures, and low moisture.
The dandelion is often considered a weed, especially in lawns, but it is increasingly being recognised in its native regions as useful for attracting birds and pollinating insects. In one study, it ranked as the fourth most important source of pollen. Although dandelion pollen is considered to be an early food resource for some emerging pollinators in spring, it has also been found to lack certain essential nutrients and can lead to declining brood health for bees. The leaves, flowers, and roots are sometimes used as food and in Medical herb.
The leaves are long and wide, and they 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 cuplike bracts that hold the florets) are composed of 12 to 18 segments; each segment is reflexed and sometimes glaucous. The lanceolate-shaped bractlets are arranged in two series, with acuminate apices. The wide involucres are green to dark green or brownish-green, with dark grey or purplish tips. The florets number 40 to over 100 per head, having yellow or orange-yellow corollas.
The fruit, called cypselae, range in colour from olive-green or olive-brown to straw-coloured or greyish; they are oblanceoloid in shape and long, with slender beaks. The fruit have 4 to 12 ribs that have sharp edges. The silky pappi, which form the parachutes, are white to silver-white in colour and around 6 mm wide. Plants typically have 24 or 40 pairs of chromosomes, while some have 16 or 32 pairs.
The taxonomy of the genus Taraxacum is complicated by apomictic and polyploid lineages, and the taxonomy and nomenclatural situation of T. officinale is not yet fully resolved. The taxonomy of this genus has been complicated by the recognition of numerous species, subspecies and microspecies. For example, the UK flora currently includes 239 species (of which 58 endemism and 45 non-native), and Rothmaler's Flora of Germany accepts roughly 70 microspecies.
T. officinale has a fossil record that goes back to glacial and interglacial times in Europe.
These European dandelions can be divided into two groups. The first group reproduces sexually, as do most seed plants. This group consists of dandelions that have a diploid set of chromosomes, and are sexually self-incompatible. Sexual reproduction involves a reduction of the somatic chromosome number by meiosis followed by a restoration of the somatic chromosome number by fertilisation. Diploid dandelions have eight pairs of chromosomes, and meiosis is regular with normal pairing of homologous chromosomes at the metaphase I stage of meiosis.
The second group consists of polyploid (mostly triploid) apomicts, meaning that both a viable embryo as well as a functional endosperm is formed without prior fertilisation. In contrast to the sexual diploids, the pairing of chromosomes at metaphase I in triploid apomicts is strongly reduced. However pairing is still sufficient to allow some recombination between homologous chromosomes.
A third taxon sometimes formerly considered a subspecies Taraxacum officinale subsp. ceratophorum (Ledeb.) Schinz ex Thellung, is now generally treated as a separate species, Taraxacum ceratophorum. It has a Holarctic realm distribution.
The Latin specific epithet officinale refers to the Latin word for 'medicinal' or 'of the apothecaries'.
T. officinale has many English common names (some of which are no longer in use), lion's-tooth, cankerwort, milk-witch, yellow-gowan, Irish daisy, monks-head, priest's-crown and puff-ball; other common names include, faceclock, pee-a-bed, wet-a-bed, swine's snout, white endive, and wild endive. The balls of seed heads are called "clocks" in both British and American English or "blowballs".
The common name dandelion comes from the French language dent de lion, or "lion's tooth", in reference to the plant's jagged-edged leaves. "Pee-a-bed" and "wet-a-bed" reflect the modern French term for the plant, pissenlit. This name and all those that imply ramped-up urine production refer to the well-known diuretic properties.
The plant grows in temperate regions of the world in , on roadsides, disturbed banks, shores of waterways, and other areas with moist soils. They are very hardy plants, able to grow in a variety of environments, and are tolerant of crowding, extremes of temperature, and low moisture.
The plant is coveted by collectors in regions where the plant is trickier to grow such as the tropics, where people would often resort to smuggling seeds from overseas.
T. officinale can serve as an Bioindicator 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 colonist 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. The seeds are also a common contaminant in crop and forage seeds. The plants are adaptable to most soils and the seeds are not dependent on cold temperatures before they will germinate but they need to be within the top of soil. Dandelions can also regenerate themselves from fragments of taproot.
T. officinale is food for the of several Lepidoptera (butterflies and moths), such as the tortrix moth Celypha rufana. See also List of Lepidoptera that feed on dandelions.
Even though dandelion pollen is of poor nutritional quality for , they readily consume it, and it can be an important source of nutritional diversity in heavily managed monocultures such as that of blueberries, or in early spring, as one of the first flowers to bloom. Honey bees have not been shown to lower their pollination activity on nearby fruit crops when foraging on dandelions.
While not in bloom, this species is sometimes confused with others, such as Chondrilla juncea, that have similar of foliage. Another plant, sometimes referred to as fall dandelion, is very similar to dandelion, but produces "yellow fields" later. Its blooms resemble some of the species of Sonchus, but are larger.
The dandelion thrives in conditions of elevated carbon dioxide, growing to a higher biomass and producing a larger number of viable seeds. Therefore, it is anticipated that the dandelion will become more competitive and widespread as atmospheric carbon dioxide levels increase.
It is increasingly being recognised in its native regions as an excellent wildflower for attracting pollinating insects and birds that feed on the seeds. In one study, it ranked as the fourth most important pollen source, after Salix, meadowsweet and Rubus fruticosus.
Dandelions are harvested from the wild or grown on a small scale as a leaf vegetable. The leaves (called dandelion greens) can be eaten cooked or raw in various forms, such as in soup or salad. They are probably closest in character to Mustard plant greens. Usually the young leaves and unopened buds are eaten raw in salads, while older leaves are cooked. Raw leaves have a slightly bitter taste. Dandelion salad is often accompanied with hard-boiled eggs. The leaves are high in Vitamin A and vitamin C, as well as iron, phosphorus, and potassium.
Dandelion flowers can be used to make dandelion wine, for which there are many recipes. Most of these are more accurately described as "dandelion-flavoured wine", as some other sort of fermented juice or extract serves as the main ingredient.Gibbons, E. Stalking the Wild Asparagus. David McKay, New York. 1962. It has also been used in a saison ale called Pissenlit (the French word for dandelion, literally meaning "wet the bed") made by Brasserie Fantôme in Belgium. Dandelion and burdock is a soft drink that has long been popular in the United Kingdom.
Another recipe using the plant is dandelion flower jam. In Silesia and other parts of Poland and the world, dandelion flowers are used to make a honey substitute syrup with added lemon (so-called May-honey). Ground roasted dandelion root can be used as a non-caffeinated dandelion coffee.
|
|
