Though related to the genus Calla, a calla lily is neither a calla nor a lily. It is part of the Zantedeschia genus and the Araceae family. Though it's most often thought of as a white flower, the cala lily actually grows in a wide variety of colors, such as yellow, orange, pink, purple, mauve, green and black.
The calla lily originated in the southern regions of Africa up to the northern parts of Madagascar. The biologist Carolus Linnaeus gave them their name.
The website Calla Lily Guide says this about the striking flower: "It became a major hit in Europe and is still very popular, especially as a wedding flower, although it has been known to appear at funerals as well."
In the role of Terry Randall in the 1937 film "The Stage Door," Katharine Hepburn says, "The calla lilies are in bloom again. Such a strange flower -- suitable to any occasion. I carried them on my wedding day, and now I place them here in memory of something that has died."