A genus of 422 species of flowering annual, biennial, and perennial plants that are commonly known as the cranesbills. It is found throughout the temperate regions of the world and the mountains of the tropics, but mostly in the eastern part of the Mediterranean region. These attractive flowers will grow in any soil as long as it is not waterlogged.

Confusingly, "geranium" is also the common name of members of the genus Pelargonium, which were formerly classified in the cranesbill genus. In the United States, true Geraniums are frequently distinguished from the less hardy Pelargoniums as (rather redundantly) "hardy geraniums" by gardeners and in the horticultural trade. One can make the distinction between the two by looking at the flowers: Geranium has symmetrical flowers, while Pelargonium has irregular or maculate petals. Other former members of the genus are now classified in genus Erodium, including the plants known as filarees in North America.

from: Wikipedia