Most people are familiar with the ‘windowsill geranium’ and other Pelargoniums such as the scented-leaved ones.
Apart from two Turkish species all Pelargonium have their origins in South Africa. My own fascination is with those species adapted to summer drought by dying back to a dormant underground tuber during the heat of summer. They have green leaves during winter but these die off in late spring, which is when most species produce their flowers. You will see from the pictures below that the leaves are absent or dry, the exception being the first one shown, P. incrassatum, which tends to flower a little earlier when leaves are still active.
I find them all easy to grow in a frost free greenhouse and they produce abundant seed if hand pollinated. Some species are recognised as potentially invasive in parts of the world with similar climate to South Africa. No such danger here in the UK!
The species below are all members of the subdivision of Pelargonium called section Hoarea. The late Charles Craib wrote a great but hard to find book on this section, with wonderful illustrations by Gillian Condy.