Round-leaved Orchid

Photo: Marcia Rubin

I like orchids as much as the next botanist. So, following a fab time at the annual Bobolinks at Byers Woods festival back on June 22, I made plans to visit nearby Mohican State Forest. There, I knew, the interesting Round-leaved Orchid, Platanthera orbiculata, should still be in bloom. It had been too many years since I had made the acquaintance of this orchid, and a visit was long overdue.

Fellow photographer Marcia Rubin joined me, and she was good enough to share this photo of your narrator in the humus and at eye-level with an orchid. Shooting Round-leaved Orchids is a challenge. They grow in the dense shade of summertime forests, and heavy canopy cover excludes much light. Flash is pretty much a necessary evil, and that tentlike thing attached to my camera is a Lumiquest Softbox, which softens the light from the camera's Speedlite. I even brought my tripod - which I rarely do - but I've found that I can steady the camera fairly well by laying on the ground and using my arms as braces.

Even with props, this orchid is tough to shoot, and I didn't like most of my images. Partly it is the plant's morphology that makes a killer shot hard to obtain: big cool-looking leaves flat on the forest floor, with a spindly little stalk with small greenish-white flowers rising eight or ten inches overhead.

Anyway, Round-leaved Orchid is a rarity in Ohio, barely extending eastward into Ohio. Where it does grow, such as in Mohican, there can be plenty though. Those big flashy leaves lay flat on the leaf litter, and the plant won't take much in the way of competition from other plants. It also, like many other orchids, is irregular in its flowering from year to year. We found only this one specimen in bloom, but saw other non-flowering plants.

The big round leaves are very interesting, and fairly conspicuous. They're shiny, thick, and fleshy, as if carved from green meat. Given the gloom of the dark forests in which they grow, it can be rather easy to pass them by, though.

Just about every species of orchid that I've crossed paths with has intricate, interesting flowers, and Round-leaved Orchid is no exception. What they lack in splashy coloration is compensated for by a fascinating structure. The long appendage hanging down is the nectary spur. It contains the sweet stuff that lures in night-flying moths, which are the pollinators. Ohio orchid authority Warren Stoutamire has captured two species of Noctuid moths at Platanthera orbiculata flowers, and other species may be part of this orchid's life cycle as well.

The flowers were beginning to show their age, but we can see the overall shape and structure. A tiny insect of some sort has taken refugia in this blossom. I suspect that Round-leaved Orchids put off a fragrance at night, which lures in their moth pollinators. An interested moth will sidle up to the flower, and work its long proboscis into its center and down into the aforementioned spur. Such close proximity will force the moth's face into contact with the flower's pollinia, and when done the pollen-dusted moth will (hopefully) flutter off to pollinate another orchid.