|Taraxacum officinale subsp. var.||Blowball, Dandelion, Wet-a-bed|
Taraxacum officinale, the Common Dandelion (often simply called "dandelion"), is a herbaceous perennial plant of the family Asteraceae (Compositae). 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.
Taraxacum officinale grows 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 foliage is upright growing or horizontally orientated, with leaves having narrowly winged petioles or they are unwinged. The stems can be glabrous or are sparsely covered with short hairs. 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 typically have 24 or 40 pairs of chromosomes but some plants have 16 or 32 chromosomes. 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,
The plant prefers light (sandy), medium (loamy) and heavy (clay) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils and can grow in very alkaline soil. It can grow in semi-shade (light woodland) or no shade. It requires moist soil. The plant can tolerate maritime exposure.
A very easily grown plant, it succeeds in most soils, though it prefers a well-drained humus-rich neutral to alkaline soil in full sun or light shade[37, 238]. A very hardy plant, tolerating temperatures down to at least -29°c. The dandelion is a common weed of lawns and grassy places. Though it has a bitter flavour, the plant is often cultivated as a salad crop and as a medicinal plant, especially in parts of Europe. There are some named varieties with larger, more tender and less bitter leaves. Dandelions can provide edible leaves all year round, especially if they are given a small amount of protection in the winter[K]. A valuable bee plant and an important food plant for the caterpillars of many butterfly and moth species[4, 24, 30, 54], it grows well in a spring meadow. A deep rooting plant, it has roots up to 1 metre long and brings up nutrients from lower levels of the soil. An excellent plant to grow in lawns, if the lawn is cut no more than fortnightly then the dandelions will provide a good quantity of edible leaves[K]. Grows well with alfalfa[18, 201]. Another report says that it inhibits the growth of nearby plants. This is probably a reference to the fact that the plant gives off ethylene gas, this gas is a hormone that promotes the premature ripening of fruits and also induces the premature fruiting of plants, thereby stunting their growth[14, 18]. T. officinale is not a valid name for this species, but no valid name has as yet been ascribed to it. This is actually an aggregate species of many hundreds of slightly differing species. Most seed production is apomictic which means that plants produce seed non-sexually and all seedlings are clones of the parent, thus small differences are maintained.
Seed - sow spring in a cold frame and either surface-sow or only just cover the seed. Make sure the compost does not dry out. Germination should take place within 2 weeks, though 2 weeks cold stratification may improve germination. Prick out the seedlings into individual pots when they are large enough to handle, choosing relatively deep pots to accommodate the tap root. Plant them out in early summer. Division in early spring as the plant comes into growth.
Pests and diseases
- 'Amélioré à Coeur Plein' - A very distinct cultivar, surpassing the wild plant not so much in size as in the very great number of leaves, which form a regular tuft of clump, instead of a plain rosette. It yields a very abundant crop without taking up much ground, and blanches very easily, and indeed, almost naturally.
- 'Broad Leaved' - The plant has large broad dark green leaves, more deeply lobed along the axis of the leaf than the wild form. The leaves are thick and tender. Plants are semi-erect in habit, and the leaves are easily blanched. In rich soils they can be 60cm wide. Plants do not go to seed as quickly as French types.
- 'Vert de Montmagny' - This form has large long dark green leaves, well lobed and denticulated. They may be blanched or not. Vigorous and productive plants, they are best sown in early spring or autumn.
- Taraxacum officinale ssp. ceratophorum (Ledeb.) Schinz ex Thellung which is commonly called Common dandelion, fleshy dandelion, horned dandelion or rough dandelion. It is native to Canada and the western US.
- Taraxacum officinale ssp. officinale G.H. Weber ex Wiggers, which is commonly called Common dandelion or wandering dandelion.
- Taraxacum officinale ssp. vulgare (Lam.) Schinz & R. Keller, which is commonly called common dandelion.
Standard Cyclopedia of Horticulture
Dandelion (i. e., dent de lion, French for lion's tooth; referring to the teeth on the Lvs.). The vernacular of Taraxacum officinale, Weber, a stemless perennial or biennial plant of the Compositae, a common weed, much collected in spring for "greens" and in improved forms sometimes grown for that purpose.
Dandelion is native to Europe and Asia, but is naturalized in all temperate countries. On the Rocky Mountains and in the high North are forms that are apparently indigenous. A floret from the head of a dandelion is shown in Fig. 1218. The ovary is at e; pappus (answering to calyx) at a; ray of corolla at c; ring of anthers at b; styles at d. The constricted part 1218. Floret of Dandelion at e elongates in fruit, raising the pappus on a long stalk, as shown hi Fig. 1219; and thus is the balloon of the dandelion formed. A dandelion plant, with its scattering fruits, is shown in Fig. 1220. Another species of dandelion is also naturalized in this country, but is not so common; it is the red-seeded dandelion (T. erythrospermum, Andrz.), with red fruits, not reflexed involucral scales, and shorter beak.
The dandelion is much prized for "greens." For this purpose it is cultivated in parts of Europe; also about Boston and in some other localities in this country. There are several improved large-leaved varieties, mostly of French origin. Some of these named forms have beautiful curled leaves. Seeds are sown in the spring, and the crop is gathered the same fall or the following spring,—usually in the spring in this country. Commonly the seeds are sown where the plants are to stand, although the plantlets may be transplanted. The plants should stand about 1 foot apart each way, and a good crop will cover the land completely when a year old. Sandy or light loamy soil is preferred. The crop is harvested and marketed like spinach. The leaves or heads are often blanched by tying them up, covering with sand or a flower-pot. The plants are sometimes grown more closely in beds, and frames are put over them to force them. Roots are sometimes removed from the field to the hotbed or house for forcing. When treated like chicory (which see), the roots will produce a winter salad very like barbe de capucin. Roots of dandelion dug in fall and dried are sold for medicinal purposes in drug-stores under the name of Taraxacum.
- Plants for a Future - source of some creative commons text
- ↑ http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=220013281
- ↑ Template:Citation
- ↑ Rose, Francis (1981). The Wild Flower Key. Frederick Warne & Co. pp. 388,391. ISBN 0-7232-2419-6.
- ↑ http://plants.usda.gov/java/profile?symbol=TAOFC