Friday, June 17, 2011
NIGHT-FRAGRANT ORCHID: ANGRAECUM DIDIERI
It's time for another botanical post. For some reason a lot of my orchids have been blooming this June. One surprise was the huge white flower that appeared one day a couple of weeks ago on my Angraecum didieri plant. The flower is almost as big as the plant itself, and is pure white with a long nectar spur and a broad bowl-shaped lip. In the photo you can see the nectar spur off to the right, behind the flower. Best of all, this orchid is powerfully fragrant at night. The scent is like strong ylang-ylang combined with smoky clove, and is almost identical to the scent of Brassavola species like nodosa and cordata, and hybrids like Brassavola Little Stars.
Angraecum is an African genus of orchids, mostly native to Madagascar. Brassavola orchids are native to Mexico and Central America. The two groups are not related, so it amazes me that they have evolved virtually the same fragrance. Both groups release their fragrance at night, both are white, and both are pollinated by moths. Ylang-ylang is light yellow in color and pollinated by moths, so there is obviously something about light colors and that type of spicy-floral scent that attracts moths no matter which hemisphere they live in.
A large relative of my blooming orchid, Angraecum sesquipedale, has an 18-inch (45 cm) nectar spur, with just a few drops of sweet stuff at the very bottom. When Charles Darwin first saw this species growing in Madagascar, he hypothesized that in order for it to be pollinated, there must be a moth with a tongue long enough to reach all the way to the bottom of the nectar spur. In fact, some years after Darwin’s death, the pollinator was discovered, with a tongue just the right length. Presumably there's a smaller moth with a tongue the right length for Angraecum didieri, too.