Tipularia discolor, the Cranefly Orchid

article by Heather Bedford, Certified VMN and NNMN member, photos by Heather Bedford

I highly enjoy winter hikes. The underbrush is often bare of leaves, enabling one to have better visibility of the forest floor and the small plants that survive the cold and grow there. One of the plants that I find highly visible in the winter is Tipularia discolor or Cranefly Orchids. Cranefly Orchids were one of the first orchids I learned to identify using just the leaves. The purple underside of the leaves was a hidden surprise that sparked my curiosity and fueled my desire to learn more about the story of this abundant orchid. Unfortunately, my search for ethnobotanical resources on the Cranefly Orchid yielded very little. However, learning about the relationships this orchid shares with its environment was equally as fascinating.

First, we can’t talk “plant” unless we talk “botany”. Cranefly orchids are perennials that spring from corms. In mid to late autumn, they often produce a single, hibernal, ovate-elliptic leaf that tapers to a point. It is dark green on top and vibrant purple on the underside. The leaf can also have purple spots on the top.

As a side note, I have also seen leaves that were entirely purple. The leaves are also a little plicate, or have a mild folded, fan-like effect. The leaves give way as spring marches forward. Then once the heat of summer hits in July and August, a raceme of tiny, dense, asymmetrical flowers goes on full display. The inflorescence is often a translucent greenish yellow color with purplish pink accents. It has 4-8 small oblong petals and a purplish pink spur which produces nectar. The fruits are small drooping capsules that can often be seen lingering through the winter months. The name “Tipularia” comes from tipula and aria which means to “resemble a cranefly”. Discolor is used to indicate that it will change color. (Weakley, Ludwig, & Townsend, 2012)

Like most orchids, growing Cranefly Orchids requires very specific conditions. They prefer oak and pine forests and acidic soil. They reproduce by seeds and spreading corms. The seeds can only germinate on decomposing wood. Creating seeds also requires an enormous amount of energy so they do not flower every year. There is also a correlation between the summer temperatures and the overall seed fertility. Excessive summer heat has a negative impact on the seed germination rate. It has also evolved an array of features to help itself absorb nutrients in the low light understory of the forest floor. One evolved feature is the relationships it has developed with the other species that share its environment. The other is the unique coloring it has. (Rasmussen & Whigham, 1998)

Mycorrhizal fungi play a key role in providing nutrients to Cranefly Orchids. Like most orchid seeds, mycorrhizal fungi are required for seed germination. However, as the plants mature, protocorm supporting fungi continues to provide support throughout its life cycle. Tulasnella sp. and Protomerulius madidul are the two fungi that have been discovered growing on the corms. It has even been observed that shade and drought will increase the fungal count. The plant itself seems to parasitize the fungi. I’m not sure how that helps the evolutionary strategy of the fungi, but for orchids in low light conditions, it certainly helps. (McCormick, Burnett, & Whigham, 2021).

Cranefly Orchids rely on nocturnal moths to pollinate their small flowers. The moths are attracted to nectar located in the spur and while feeding, pollinia will stick to its eye, in hopes of being deposited into another flower. Army worm moths and common looper moths are just two of the various noctuidae that pollinate these orchids. (Whigham & Margaret, 1980).

The unique coloring of the Cranefly Orchid leaf is what originally caught my attention. I noticed a few lingering species, like a woodland aster, that also had purple under the leaves. At the time, I was told that it assisted with photosynthesis in low light conditions. It is a prominent feature in many understory plants in tropical rainforests. In the plant world blue and purple colors are caused by the presence of anthocyanins. In human foods, anthocyanins are the primary antioxidant found in berries, dark colored fruits, and in vegetables bred to display purple coloring, like purple cabbage. They can sometimes be used as dye but since they are water soluble, they really lack staying power. However, in plants, anthocyanins have multiple uses.

“These functions include camouflage and defensive signaling, fungal defense, light attenuation, serving as a carbohydrate sink, reactive oxygen species (ROS) scavenging, and metal chelation. While it is well understood that changes to anthocyanin chemical structure in floral organs can affect pollinator preference, it is less clear why plants would synthesize one anthocyanin rather than another in vegetative organs. In addition to affecting color, anthocyanin chemical structure can also influence antioxidant activity, absorption of green and UVB light, and antimicrobial activity” (Hughes, 2021).

As many of you know, my interest in plants predominantly lies in the realm of ethnobotany, folklore, and their overall relationship to people. Historically, I found no real mention of it as a food or medicinal plant. I discovered that deer would eat the leaves when they face food scarcity. I also learned that small mammals, like moles and voles, consume the corms. I have personally tasted the leaves just to determine the energetic qualities of it. I found it to be dry and cool with a slightly bitter taste. Bitter often indicates the presence of alkaloids and since I couldn’t find any real data on the subject, I chose to not consume them. I did find several adventurous people on the internet that have eaten the corms. They reported stomach discomfort when consumed raw but was very “potato-like” when cooked. I’m not that adventurous.

Scientists are learning more each year about mycelium, forest floor ecology, pollinators, plants, and the web in which they are all interwoven. The Cranefly Orchid is a small piece of a much larger picture we have yet to fully understand. While it may not serve a direct benefit to humans, it does offer a glimpse of beauty and wonder on blustery winter days when exploring the forest.

References:
Hughes, N. M. (2021, Feb). The same anthocyanins served four different ways: Insights into anthocyanin structure-function relationships from the wintergreen orchid, Tipularia discolor. Plant Science.
McCormick, M., Burnett, R., & Whigham, D. (2021,10). Protocorm-SupportingFungiAreRetained Roots of Mature Tipularia discolor Orchids as Mycorrhizal Fungal Diversity Increases. Plants, p.1251.
Rasmussen, H.M., Whigham, D.F. (1998).
Importance of Woody Debris in Seed Germination of Tipularia discolor. American Journal of Botany, pp.829-834.
Weakley, A.D., Ludwig, J.C., & Townsend, J.F. (2012). Flora of Virginia. Fort Worth: Botanical Research Institute of Texas Press.
Whigham, D., & Margaret, M. (1980,4). Studies on the Pollination Ecology of Tipularia discolor. American Journal of Botany, pp. 550-555.