A perennial, the Dandelion is a member of the sunflower family, the name comes from the French, 'dents de lion' ("teeth of the lion") due to the shape of the leaves. A native to Europe, it is now widespread as it was taken around the world for its medicinal and culinary, uses. Dandelions are popular with beekeepers as they are an early source of nectar.
The dark green leaves form a rosette close to the ground and are not killed by close mowing. The fleshy tap root goes down vertically and a small portion can regenerate if left in the soil. It is a resilient plant and can force its way up through tarmac. If it is cut off below soil level it comes back as a multi-crowned plant.
The flower buds form at the centre of the rosette in early spring and are lifted up by a hollow stem which can reach 45 cm if in long grass, the yellow composite flowers open to be pollinated by insects or the wind. The bracts at the back of the flower close up again and the seeds ripen. The stem which had lowered during the ripening, rises again to a higher level and the bracts open to reveal a sphere of fluffy parachutes each carrying a seed. Even if severed they still manage to open, so they should not be left after mowing.
The flowers can be used to make wine, the leaves boiled like spinach or added uncooked to salads, and the roots used as a vegetable or roasted and brewed for a coffee-like beverage. Dandelions used to be grown in unheated greenhouses to provide salad leaves in winter. They contain potassium, sodium, phosphorus and iron. The leaves are a richer source of vitamin A than carrots and also have some vitamins B, C and D.
It is a mild laxative and diuretic, has been used as a tonic and blood purifier, for skin conditions, joint pain, eczema and liver conditions such as hepatitis and jaundice.

Dig up the whole plant using a fork to reduce the likelihood of breaking the root. If repeated a few times you can eventually rid a lawn of an infestation, but there will always be a return form new seed which float in; they can travel up to 10km on a moderately windy day, but most fall close to the parent. The younger the plant is the better the chance of complete removal. It often germinates close to other plants after the floating seed became trapped, the most difficult instance is in a clump-formimg plant where it has grown in the centre. To remove it lift the plant and tease out the weed or paint the leaves with a systemic weedkiller.

A herbicide like Glyphosate is best. Pull off any flowers as they can mature and produce seed before the chemical can act. In the lawn a selective weedkiller should work, or use Gylphosate as a spot weeder.

Nicholas Culpepper
(17th century astrologer-physician)
"It has an opening quality and, therefore, very effectual for removing obstructions of the liver, gall bladder and spleen and diseases arising from them, such as jaundice.
It openeth the passages of the urine both in young and old and will cleanse ulcers in the urinary tract. For this purpose the decoction of the roots or leaves in white wine, or the leaves used as pot herbs are very effectual. It is a wonderful help in cachexia, the severe wasting condition in severe illness. It also procures rest and sleep in those with fever. The distilled water can be drunk in pastilential fever and be used as a wash for sores. This common herb hath many virtues, which is why the French and Dutch eat them so often in the spring."