Dandelion

Dandelion (Taraxacum) is a perennial or biennial plant from the family Asteraceae.
It's interesting that they tend to be mostly polyploid. It also has a lot of different species - around at least 60 - and one would say it's just one flower. Reportedly some of the species are spread e.g. only in one mountain valley or so; while in the second valley there are different dandelion species. The plant originated in Europe but spread throughout the whole world.
It is usually considered to be a weed, however it has a lot of outstanding qualities. Leaves can be eaten either raw or cooked. They contain a lot of vitamins and a lot of iron. Sap can be used as a mosquito repellent. The root can be roasted and used as a coffee substitute. And finally the blooms can be used to make dandelion wine or dandelion honey (ok, it technically isn't honey, but let's call it so).
Dandelion extracts are used as a diuretic drug.
Blooms are very vulnerable to rain and very sensitive to the amount of sunlight. A lot of butterflies feast on dandelion blooms.