Thanks to Ruth for today's write-up!

To shed light on an ever-confusing sector of the horticultural world, let's make clear the differences between geraniums and their close relatives, the pelargoniums. Many of the plants we purchase at garden centres under the common name geranium are, in fact, members of the genus Pelargonium. When Linnaeus originally named the genus Geranium, he grouped the genera Geranium and Pelargonium together. The two were later split in 1789, by the French botanist Charles L'Heritier de Brutelle. The name geranium has remained in use, though, as a common name for both of these members of the same family, the Geraniaceae.

The picture here is of a true Geranium in the botanical sense. It is commonly called mourning widow. Unlike the floriferous, showy type of "geraniums" (i.e., members of the malleable and easily-hybridized genus Pelargonium) used for annual color, its flowers are more discrete and of a sultry dark burgundy or black hue.

The mourning widow is native to western and central Europe, but it has also naturalized in other parts of Europe as well as portions of Africa and Asia. It is commonly found growing in woodlands and sub-alpine meadows.

Thanks to AnneTanne@Flickr of Belgium for sharing this picture via the UBCBG Botany Photo of the Day Flickr Pool.