Finding a Match
By Karen Menard
Sticking together like glue, unique plants like one-flowered broomrape (Orobanche uniflora), recently discovered at Fallen Timbers Battlefield, and blue-stemmed goldenrod (Solidago caesia), are perfect examples of a plant parasite-host relationship that occurs right under our feet, trailside.
Most of us don’t realize the subterranean pursuit that is unfolding just below ground. In order to make its life complete, the Orobanche—a dainty, leafless plant--no taller than just a few inches, has to find itself in the right location situated next to its special “match” or compatible host plant species to grow old with.
Orobanche lacks chlorophyll and is incapable of making its own food. Instead, it relies on close connections with other plant species like sedums, goldenrods, sunflowers and saxifrages for life-giving sustenance. When a host match is made, the Orobanche attaches itself like glue via specialized root structures known as “haustoria” in order to be able to successfully extract carbohydrates, nutrients and water for itself. This parasitic relationship in this case hasn’t had any effect on the goldenrod host. However, in some cases, other species of Orobanche can have effects on their hosts— yet, keep in mind that parasitic plants do play important roles in our ecosystems, affecting nutrient cycling.
Locating this species is not an easy task today due to fragmented landscapes and decreased natural area biodiversity. Historically, this species was most likely more abundant in northwest Ohio with “matches” residing in closer proximities, making connections easier. Today, rich, high quality mesic woodland ecosystems at like Fallen Timbers still provide good habitat for a diversity of unique plant species like these.
Did You Know?
The flowers of this plant are cross-pollinated by long-tongued bees such as the larger, American bumblebee (Bombus pensylvanicus). The Fallen Timbers population of Orobanche uniflora is the first documented species occurrence in the Metroparks.
Photos: Karen Menard