Coralroot Orchids


I recently noticed some coralroot in the Turtle Mountains.  Coralroots are members of the orchid family.  There are three species documented in North Dakota with collections from Benson, Bottineau, Dunn, McKenzie, Pembina, Rolette, and Stark counties.

Some of you listeners may have seen coralroot, but perhaps didn’t know what it was.  It’s a reddish-purplish plant about eight inches tall with small red flowers and pale stripes (no green on the stem or small leaves).

Orchids have symbiotic relationships with soil fungi called mycorrhizae.  The mycorrhizae actually grow into the plant’s roots and supply the plant with water and nutrients in exchange for a steady supply of sugar.  Both organisms benefit in this relationship biologists call mutualism.

But coralroot is a different (and unusual) situation.  Coralroot doesn’t have chlorophyll, so it can’t carry out photosynthesis and make sugar.  As a result, it’s totally dependent on the mycorrhizae.  That’s not mutualism; it’s more like parasitism, with the orchid being the parasite.

And there’s another strange twist to this story.  Here, as Paul Harvey used to say, “is the rest of the story.”  Recent studies have indicated that coralroot actually obtains its sugar from another plant (or plants) which share the same mycorrhizae.  The mycorrhizae functions as a conduit, enabling coralroot to parasitize the other plant.  Consider for a moment all the biological activity that goes on underground.  We have a lot to learn about this hidden world.  More research is needed to definitively determine what’s going on here, but it appears that coralroot is an “imposter.”

We think of orchids as rare and exotic, so it may surprise you that the orchid family may be the largest family of flowering plants, with at least 24,000 species.  They’re rarely abundant, and most are tropical.  If we lived in the tropics our perception of orchids would be quite different.  Only about 140 species are native to the United States and Canada.  North Dakota only has 14 species, about half of which are listed as threatened or endangered.

Because of their beauty and mystique, there’s often a real temptation to transplant orchids, but their habitat requirements are so restricted that these efforts usually fail (plus they are also protected species).    So if you’re fortunate enough to see these little gems, take a little extra time to savor them in their natural habitat.









Chuck Lura

Natural North Dakota is supported by NDSU Central Grasslands Research Extension Center and Minot State University-Bottineau, and by the members of Prairie Public. Thanks to Sunny 101.9 in Bottineau for their recording services.

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