The Cranefly Orchid Lives on One Leaf in Winter

Cranefly orchid flower (photo credit: thealphawolf, CC 3.0 via Wikimedia)

Orchids are masters of both deception and evolution (in the plant world, the two go hand-in-hand). With orchids, what you see is almost never what you’ll get when the flower is in bloom. One of the many surprises these plants have up their sleeves is their ability to be resourceful and economical when it comes to energy. The polar opposite of the flashy foliage sported by jewel orchids, each cranefly orchid gets its energy from just one plain-looking leaf every year. 

The cranefly orchid leaf is green on the top, purple on the underside, and has black spots that I personally would mistake for a fungus, but aren’t. The leaves are so nondescript that if you saw one, you’d probably assume it was a leaf fallen from a nearby tree and not think twice about it. But that single leaf is up to something awesome, because of course it is—these are orchids we’re talking about!

Cranefly orchid leaf (photo credit Judy Gallagher via Flickr, CC 2.0)

Cranefly orchids are native to the eastern U.S., where they commonly grow on forest floors. Not a lot of sunlight reaches them through the tree canopy, so they grow a single leaf to soak up the winter rays that can now make it to the ground because the tree leaves are gone. Unlike most plants, cranefly orchids photosynthesize during the winter and stop once the tree canopy has grown back. Their leaves are “hibernal,” meaning that they grow while other plants are hibernating.

In late spring when leaves on other plants are emerging, the cranefly orchid leaf dies off. A few months later, in late summer or early fall, the plant will start blooming. Each tall (12-18 inches) flower stalk can hold dozens of small flowers. Apparently, the blooms look like crane flies—not that I know what those look like. But what’s strange is that the flowers aren’t symmetrical.

Blooming cranefly orchid (Photo credit: Fritzflohrreynolds, CC BY-SA 3.0 via Wikimedia Commons)

This asymmetrical arrangement helps increase the chances of pollination. The moth that pollinates these plants is attracted to the nectar, and as it goes rooting around for it, pollen from the blooms rubs onto its eyes, where it sticks until the moth brushes up against another flower. The blooms are positioned to maximize the chances of its pollen touching the moth’s eye or eyes. 

Unlike most orchids, which reproduce via pups or keikis, cranefly orchids produce corms—small, almost acorn-like bulbs from which new plants grow (alocasias reproduce this way). Apparently, those corms also serve as food for animals like deer.

Cranefly orchid corms (photo credit: cotinis, CC 2.0 via Flickr)

Like flying duck orchids, cranefly orchids have a symbiotic relationship with fungal networks and are picky about their soil and other growing conditions, so they’re not typically sold at nurseries or raised by orchid cultivators. But if you live on the east coast, you might be able to find and enjoy these plants in the wild. If you take a walk in the woods at the beginning of spring, you can look for those single green leaves with a secret so you know where to come back later in the summer for the blooms.