Pelargonium - from Pelargos Greek for Stork, hence the common name of Storksbill - referring to the similarity of the rostrum of the schizocarp to a Stork's Bill.
The genus includes more than two hundred natural species and nowadays many thousands of cultivated hybrids. While the majority of species is South African, some occur in Tropical Africa, Syria, Australia and on a few islands in the Indian Ocean.
The flowers of the Genus Pelargonium are Zygomorphic, or irregular. Unlike the Genus Geranium - which has five equal-petalled flowers, Pelargoniums have two distinctly different upper petals - sometimes larger, sometimes smaller - than three uniform lower petals. So it can only be divided equally on one plane.
Pelargonium seeds are carried by the wind and twist themselves into the ground by expansion and contraction of the awn.
If you compare the flowers of the species Pelargonium echinatum and this hybrid single Zonal pelargonium cv. 'Pink Happy Thought' (constantly referred to as a 'geranium' in retail nurseries) there can be no doubt that they both stem from the Genus Pelargonium and should be so called.