Epipactis helleborine (Michigan's Upper Peninsula)

Epipactis helleborine

I came across this native orchid almost entirely by happenstance. I had stopped at a beach access point to look over at a placid Lake Michigan coastline.  Although many different flowers were growing along the coast, one particular shrub caught my eye.  There was something different, something familiar about it.  I jumped the fence to get close, and my suspicions were confirmed—this was, in fact, a wild orchid! Further observation identified it as Epipactis helleborine.

Lake Michigan shoreline--E. helleborine was growing just to the left out of view

So what do we know about this species? E. helleborine is a terrestrial orchid species that grows in wooded areas, swamps and riverbeds around the world, including parts of Europe, Asia, Africa, and North America. In fact, in the US, it's sometimes known as the "weedy orchid" because of its propensity for invading lawns and flowerbeds.  An audacious little plant!

E. helleborine distribution in the US (Adapted from: https://plants.usda.gov/core/profile?symbol=EPHE)

A recent study (May et al (Micorrhiza) 2020) provides insight into how this species is so successful across many terrains.  Like many orchids, E. helleborine develops a symbiotic relationship with mycorrhizal fungi in its root system.  Mycorrhizal fungi supply the orchid seeds with nutrients essential for germination.  Later, these fungi provide the adult orchid with a carbon source to supplement photosynthesis (organisms that get their energy from multiple sources like this are called mixotrophs).  

In the study by May et al, the authors observed E. helleborine orchids that were transplanted into pots for up to 3 years. These transplanted orchids had to grow without the aid of mycorrhizal fungal networks, relying solely on autotrophic growth (i.e. deriving all their energy through photosynthesis). May et al found that E. helleborine orchids can thrive even without fungal symbiotes. The authors suggest that this ability of the orchid to acquire nutrients through either mixotrophic (supplemented by the fungal symbiotes) or autotrophic (purely through photosynthesis) modes of growth "adds to the ecological plasticity" of these plants.

 

E. helleborine closeup

Citation: 

May, M., Jąkalski, M., Novotná, A. et al. Three-year pot culture of Epipactis helleborine reveals autotrophic survival, without mycorrhizal networks, in a mixotrophic species. Mycorrhiza 30, 51–61 (2020). https://doi.org/10.1007/s00572-020-00932-4