Now that summer is here, finding woodland wildflowers can be more of a challenge. Gone are the flashy, brightly blossomed sprites that flourished in the spring sunshine. The dark shade cast by the trees and shrubs hides the nourishing rays of our closest star. Still, if one takes the time to look, and knows where to cast one’s gaze, one can find a few shy flowers that prefer the dimmer light. I give you the pyrolas.
Pyrolas, commonly known as wintergreens, even though they are not THE wintergreen made famous in flavorings and linaments, are small inconspicuous plants that dot many of our forest floors. Overall they are unimpressive, their leaves no more than a green rosette that clings tightly to the ground. But from the center of this rosette rises a slender stalk, and from this stalk the flower(s) droop(s).
Most common in our mixed northern woods is shinleaf (Pyrola elliptica). Its flowers are a greenish white, and, like all pyrolas, hang downwards as though the plant were nodding off to sleep. If you tilt a blossom upward and take a close look (a hand lens comes in real handy about now, or a macro lens on your camera), you’ll see some of the other traits of this clan of flowers.
For example, sticking out from the center, extending well beyond the reach of the petals, is the style – part of the female productive system. The tip of the style supports the stigma, which is the part that receives the pollen. On pyrolas, the stigma is flared, or sometimes lobed, and it acts as a landing platform for the flower’s insect pollinators, most of which are flies.
Surrounding the style are the stamens, the male parts. At the tip of each stamen is the anther, which produces the pollen. Now, what’s really cool about the anthers is that they look like straws: hollow at the tip. Go ahead and grab a hand lens and take a good close look. The tips have holes! They remind me of some of the anemones one sees waving about on coral reefs. It is from these holes that the pollen is shed.
The pollen, which you will not likely see, is sticky. When the flies come in to sup at the flower, the pollen is shed upon and sticks to their furry bodies. The flies travel from flower to flower, and the pollen is transferred from their bodies to the sticky stigma. From here the pollen travels down the style to the ovary and voila! the plant is fertilized.
Pyrolas are fascinating in other ways as well. For example, they have a close relationship with the local fungi. The soil all around us is full of mycelia, the vegetative structures of many fungi. The pyrolas are what scientists call mycoheterotrophs, meaning they acquire nutrients by feeding off these mycelia. It’s a parasitic relationship. In and of itself, this isn’t all that unusual, for many forest plants have similar relationships with fungi. What makes the pyrolas stand out, however, is that they can also survive completely photosynthetically – they can make their own food. It seems that the parasitic relationship is optional for them. From what I’ve been able to determine in the literature, the exact nature of this plant’s relationship with (and without) the fungi is not well understood. There could be a good research project in this, just waiting for the right graduate student to unlock the secret.
Recently I’ve been fortunate enough to see several of our local pyrolas in bloom, including the pink, or bog, pyrola (P. asarifolia), which is a threatened species in New York State. With a little scouting around our forest floors, especially damp woodlands, you, too, can add shinleaf pyrola, one-flowered pyrola (P. secunda), one-sided pyrola (Moneses uniflora), green-flowered (P. virens)* and round-leaf pyrola (P. rotundifolia) to your life list. And if the flower gods are smiling on you, you can also add the pink pyrola, a real treat to any nature nut, even if flowers are not your passion.
* this is the one pictured above