I had to wait five years to get a digital photo of a Crested
Coral-root Orchid, Hexalectris spicata, at Blue Jay Barrens. Its last appearance was in 2008 and I was
able to capture the image in print and slide form. In 2009 I was prowling the woods with my
newly purchased digital camera, hoping to get some good shots of the Crested
Coral-root, a plant listed as potentially threatened in Ohio.
Unfortunately, this particular orchid species often skips blooming for a
year or two and my photographic attempts proved futile. I was certainly concerned at its failure to
appear for a half decade.
Crested Coral-root is a south-western species that has just
barely extended its range into southern Ohio. As is often the case with plants growing at
the extreme limits of their range, weather conditions have a significant impact
on their growth habits. Sight of a
single flower stalk on August
2, 2013 marked my first viewing of this orchid since its flowers
faded back in 2008 and was the first of many found that day.
The actual body of the plant is found below ground and it is
only the flower stalks that are exposed.
This is a plant lacking in chlorophyll, meaning no green coloration and
the inability to perform photosynthesis, the means by which energy from the sun
is used to convert carbon dioxide and water into carbohydrates and oxygen. Because the plant does not require sunlight, Hexalectris
can thrive in the shadiest of locations.
The Crested Coral-root orchids at Blue Jay Barrens grow on
dry ridge tops exhibiting shallow soil over limestone bedrock. Most of the plants are in close proximity to
mature Chinquapin Oaks, Quercus muehlenbergii, like the one shown here with a
lichen covered trunk. Even though they
can’t produce their own, carbohydrates are still necessary for the growth and
survival of the plant. To get what is
needed, the orchid steals from other plants.
It’s possible that Chinquapin Oaks are a major supplier of
carbohydrates to the Crested Coral-root Orchids. The green oak leaves work through the day
producing carbohydrates. That captured
energy is then moved to the tree roots for storage.
The act of transferring energy from tree to orchid is
accomplished through filaments of mycorrhizal fungi that link the two plants. Mycorrhizal fungi have associations with many
plants and generally trade nutrients extracted from the soil for sugars
produced by the plants. Crested
Coral-root Orchids have evolved to take all of their needs from their
associated fungi. It’s unclear whether
or not the orchid actually gives anything back to the fungus.
It’s not hard to understand why these special orchids are a
rarity. First of all, just like any
other plant, their seeds must fall in a location suitable for germination and
development. Secondly, the proper
species of mycorrhizal fungus needs to be present and able to grow on that
site. Finally, there needs to be a
compatible plant available to transfer sugars to the fungi. Weather or other environmental factors can
work on any one of the three components of this partnership with the end result
being a lack of flower production on the part of the orchid.
Other than protecting the site from disturbance, I don’t
know that there is anything I can do to improve the chances of the orchid’s
survival. I just enjoy the blooms when
they appear and hope there’s not another five year absence.
