Field Notes: Hunting for Orchids and Indian Pipe

October 7, 2011

I am riding north with Matt Richards, the Atlanta Botanical Garden’s Conservation Coordinator and orchid specialist.  We are headed to Georgia’s gold country.  It is also orchid country, where both yellow and pink lady’s-slipper flourish, and where the remaining populations of rare orchids species can be found—if you are lucky.  The orchid we are looking for today is Isotria medeoloides, or small whorled pogonia.  The U.S. Forest Services has been monitoring the plant for the past 15 years, and its numbers have been in steady decline.  

Isotria medeoloides in bloom.  Photo: Dennis D. Horn.

Our first stop is a gas station in Suches, which boasts the highest elevation of any Georgia town (just shy of 3,000 feet).  In my experience, fieldwork meet-ups tend to be at gas stations, which is convenient since you get one last visit to the bathroom and a chance to buy water and other provisions before entering the woods.  Deciduous forests aren’t the greatest for finding secluded spots for a bare-bottomed pee, especially if you are with a group that has split up to search for plants. 

We don’t have to wait at the station for long before Mike Broe arrives.  Mike is a Ph.D. student at Ohio State University working on Indian pipe, a kind of mycotrophic ("fungus feeding") plant that has no chlorophyll and spends most of its life underground. Green plants are called “autotrophs” because they are capable of feeding themselves given sun, water and carbon dioxide.  Mycotrophs take advantage of the symbiotic relationship between trees and mycorrhizal fungi.  Mycorrhizal hyphae (fungal threads) enter into the roots of the trees and the trees benefit from the increased surface area of their root system.  The trees absorb more water and minerals, and the fungus receives nutrients from the tree.  Like a little thief, Indian pipe taps into this symbiotic apparatus, reversing the flow of carbon and other nutrients to meet its own needs.

A more common Indian pipe, Monotropa uniflora, also called Ghost plant.

The only time Indian pipe and other mycotrophic plants are visible is when they flower, pushing mushroom-like through the forest duff.  The kind of Indian pipe that interests Mike is Monotropa hypopitys.  Its flower is a pale creamy white, coral pink or red.  On a recent orchid-seed collecting trip, Matt saw populations of very deep red M. hypopitys similar to ones Mike has observed in Maryland and Ohio.  From his studies of the morphology and DNA of the plant, Mike has reason to believe that this southern population may be a distinct species. When he has looked at specimens under a microscope, Mike has seen white hairs around the stile that are not present in M. hypropitys of the north: “The white hairs are very striking against the red, like Santa’s whiskers.”

Matt (right) showing Mike where we are on the map.  Better than leaving breadcrumbs.

The trail Matt leads us down is densely forested with pine and hemlock and overhung with rhododendron, creating the gloomy atmosphere favored by Monotropa.  It isn’t long before we spot the red flower spikes of M. hypopitys—as it is called for now.  After Mike’s work, it may be assigned a new classification.

M. hypopitys in its red glory.

 Mike is delighted at what he sees.

“Need anything else?  You want help finding your way out when you’re done?” Matt asks before we leave him to it.

“No,” Mike replies, “I’m in hypopitys heaven!”

***

Our next appointment is with Ronnie Ensley, our guide to the area’s Isotria populations.  Ronnie worked for the U.S. Forest Service where his job was to look for federally protected plant species on land slated for logging.  “I was the only one to apply,” Ronnie told me.  “I learned on the job.” 

Matt has great respect for Ronnie.  “There’s a generation gap between guys like Ronnie and me.  He’s gotta be at least 70, and what he knows nobody else does.  When he’s gone, that it.  It’s important to get out there with him and transfer some of that knowledge.”

Our quarry, the orchid Isotria medeoloides.  Can you see it, the light yellow, five-petaled plant in the middle?

Isotria flowered back in May, so we are looking for what remains of the plant, hopefully with seed capsules intact. It’s a small plant and is especially hard to spot in its spent state.  Also, Isotria often grows among wild cucumber, which has a very similar look.  Not every plant flowers, and in a poor growing season, fewer plants come up at all.

The site of our first search for Isotria.

The first location Ronnie takes us to is a lovely little creek-side slope.  After a search we find lots of wild cucumber and only two Isotria, neither of which have seed capsules and don’t look like they ever did.  We also find a three birds orchid, Triphora trianthophora, which bloomed somewhere between July and September.  The flowers last just a few days and are open only from midmorning to midafternoon.  Triphora in bloom is a truly rare sight.

Three birds orchid with seed capsules.

We drive to another spot and park.  Here we put on orange vests since it’s hunting season.  Rifles are banging away in the distance.  We hike into what was once a road, which is now over-grown with shrubs, sapling tulip poplars and baby hemlock.  Ronnie takes a turn off the path and heads into the forest.  How does he know where to turn?  He doesn’t use GPS or look at a map he’s marked.  Matt and I are baffled.  He just walks right up to the spot where he’s seen Istoria in the past. 

After a bit of a search, we find an Isotria with seed capsules intact. 

“You’re gonna decapitate it, aren’t you?” Ronnie asks Matt.  “I can’t watch.”

Our guide, Ronnie Ensley in the foreground.

Matt assures him that he’ll only keep around 10% of the seed.  The rest he’ll disperse in the same spot, some as raw seed and some in prepared packets to bait the fungus Isotria needs to grow.  What Matt keeps he will try to grow in the tissue culture lab back at the garden, and some will simply be stored as back up against extinction. 

At the last site I actually find an Isotria with seed.  I am quite pleased with myself since it is particularly ratty and difficult to see.  I consider myself extremely lucky to be able to come along on fieldwork.  As I see it, my first duty is not to get in the way.  My second is to be a pleasant traveling companion.  I feel especially glad when I can actually be of some use. 

Our last Isotria of the day and my first find.

 We hike back to our vehicles and part ways with Ronnie.  It’s been a good day.  We found what we were looking for—which happens as often as not in Matt’s line of work—and we collected seed. As we motor through the countryside, Matt grips the wheel and exclaims, “There is no way I could have found those plants without Ronnie.”


Sources

Brown, Paul Martin. Wild Orchids of the Southeastern United States, North of Peninsular Florida. Gainesville: University Press of Florida, 2004.

For more information about Indian pipe and other mycotrophic plants, visit the U.S. Forest Service's "Celebrating Wildflowers" page:   http://www.fs.fed.us/wildflowers/interesting/mycotrophic/index.shtml