A large population of the rare, Small Whorled Pogonia orchid in western South Carolina — 2017-05-06

On Saturday, May 5, I was fortunate enough to be guided to a special site in Oconee County, South Carolina for the rare, Isotria medeoloides or Small Whorled Pogonia orchid. My guide was a recent acquaintance, David White, who is a contract employee for the US Forest Service, doing monitoring and surveys of plants within the state of South Carolina. David is the volunteer steward for this particular plot of orchids, and he is charged by the newly formed, South Carolina Plant Conservation Alliance (SCPCA), to make periodic reports concerning the orchid’s well-being.

Here is an image of one of the plants we found at the creek-side plot:

Small Whorled Pogonia orchid Small Whorled Pogonia orchid (with a tiny inch worm on one of the sepals)

A bit of background about this orchid species:

According to the International Plant Names Index (IPNI), it was first described in 1836 by the European botanist/naturalist Constantine Samuel Rafinesque (1783-1840), but the description was not published until 1838. During that period of time (and for many years earlier), the continental US was a haven for foreign botanist to explore, finding many species that were new to science. These botanist literally filled the European herbarium cabinets with specimens of our native species.

Its species name, medeoloides (meaning “looks like Medeola“) comes from its leaves resembling those of the common, Medeola virginiana or Indian Cucumber Root. Interestingly enough, there are a number of Medeola virginiana in the immediate area, which makes it somewhat difficult to distinguish those plants from the orchid plants when performing a count. Here is an image showing both species side-by-side. Note the particular difference in the color and thickness of the supporting stem:

Side-by-side comparison of Isotria medeoloides and Medeola virginiana

The Small Whorled Pogonia orchid is federally listed as threatened. The listing of threatened and endangered species is governed by Endangered Species Act of 1973. This orchid species was originally added to the endangered listing in 1982, but was removed from the endangered listing in 1994 due to many of its populations being protected and deemed as relatively “secure”. Much of this has been accomplished by land acquisitions and conservation easements. However, not all is well — it is a species on the brink of recovery which has to compete with other plant and animal species for a limited amount of funding and other resources. These other species, themselves, may be on the edge of extinction, and may by necessity require more of these scarce resources.

This is a much-studied species, but there is still a great deal to be learned. There is a group of researchers at the Smithsonian Environmental Research Center (SERC) which is led by Melissa McCormick, who has spent considerable time and effort on a small plot in Maryland, expanding the knowledge base about this diminutive orchid. Her specialty is the study of the mycorrhizal associations or orchid-fungus symbiosis of this orchid species. Because it is believed that this orchid cannot survive without its fungal host, it is important to learn more about keeping the fungus happy so that the orchid will be happy.

This orchid species is found only in North America – mostly east of the Mississippi River. Here is a map of the eastern US with the counties of extant populations marked in red. Keep in mind that this map was drawn in 2008, so it may not be particularly accurate today. I found the map in a pdf entitled, “Small Whorled Pogonia (Isotria medeoloides) — 5-Year Review: Summary and Evaluation”. It was produced by the U.S. Fish and Wildlife Service, New England Field Office, Concord, New Hampshire:

2008 map of known populations of Isotria medeoloides in North America

There are a few populations in southern Ontario, but the large majority of them are in the continental US. Several of the historical sites (such as the one in Michigan) may be extirpated. One of the problems of monitoring this species is the fact that it may lie dormant, underground, for as many as five or more years before reappearing. So just because the leaves and flowers are not visible above ground does not mean that the plant is no longer there. The main danger to the plants is the destruction of suitable habitat. Predation by slugs, deer, and feral hogs also present a real hazard. It is felt by many botanists that Climate Change may adversely affect the health of populations of this species, especially in the southernmost extent of its range.

Before I proceed any further, I will give you the “head count” of the plants we observed at the site:

12 Sterile plants (those with leaves, but no flowers)

22 Plants with a single flower

10 Plants with two flowers

44 Plants total

We also observed several dried seed capsules from last year still standing next to the plant that produced them:

10 Plants with a single seed capsule

2 Plants with two seed capsules

To my knowledge, this is one of the largest sites for this orchid in the US! I have visited other sites for this species in other states, but many of the sites have fewer than a dozen plats — some have only one or two. Last year, there were 37 plants observed at the site. So, they seem to be holding their own. We did observe a number of tiny, young plants, giving us hope for the future.

Here are some additional images of the flowering plants that produced a single flower:

Small Whorled Pogonia orchid Small Whorled Pogonia orchid
Small Whorled Pogonia orchid Small Whorled Pogonia orchid

Small Whorled Pogonia orchid

Here are a few images of plants that produced a double flower:

Small Whorled Pogonia orchid Small Whorled Pogonia orchid
Small Whorled Pogonia orchid Small Whorled Pogonia orchid

Small Whorled Pogonia orchid

Note: A couple of years ago, my good friend David McAdoo managed to photograph a single plant in North Carolina that produced three flowers! That is almost unheard of. The same plant produced three flowers for a couple of years before disappearing. We all have high hopes that the plant is just “resting” and will reappear soon.

As I mentioned earlier, we observed a number of last year’s seed capsules. Here are a couple of images of those seed capsules:

Small Whorled Pogonia orchid with seed capsules Small Whorled Pogonia orchid with seed capsules

As evidenced by the taller seed capsules, the plant continues to grow in height after the flowers are pollinated. If the flowers are not pollinated, the plant withers and no evidence of it remains the following year.

Some of the sterile plants (those with no flowers) were very small — about 1 inch (2.5 cm) across. These were immature plants, and may take several years to mature enough to produce a flower. Here are a couple of images of those sterile plants:

Small Whorled Pogonia orchid - sterile plants Small Whorled Pogonia orchid - sterile plants

To be truthful, the image of the plant above right does have a nub of an aborted flower in the center of the leaf rosette. The plant was very small, and I figure it was just too tiny to support the flower to blooming.

Small, sterile plant with 1 cm bar for scale

Finally, I will show you two images of the habitat. For the most part, the ground where the plants grow is uncluttered. Around the periphery of that area, there are thick stands of ferns encroaching. This will require careful monitoring so that the orchids will not be competing with the ferns for sunlight. A few years ago, the canopy was opened by the death of a large Tsuga canadensis or Canadian Hemlock tree. In the past, this towering tree may have provided enough shade so that the ferns preferred to be in a sunnier spot. All of the Canadian Hemlock trees in the region are dead or dying from an infestation of an insect called Adelges tsugae or Hemlock Wooly Adelgid. It is a very small insect that suck the life juices from the new growth on the Hemlocks, effectively killing them in just a couple of years. The infestation appears as a thick, cottony mass on the underside of the leafy stem.

Small Whorled Pogonia habitat

I circled the area where one of the orchid plants is growing.

Small Whorled Pogonia habitat

Note the thick encroachment of ferns, in the above shot.

Although most of the plants are single stems scattered here and there (it is not considered a “clumping” species), there was one area where several plants were growing in close proximity. The following image will show this grouping. The blue flagging tape was placed next to each plant to facilitate the count:

small group of Small Whorled Pogonia orchids

Well, what a special treat that was for me! I did manage to take time away from my photography to help with the plant count, but I am deeply indebted to David for showing me this orchid site. We are truly blessed, if you will, to live in an area of the Southern Appalachian Mountains where there is such a high degree of plant diversity. Being an orchidophile, I am doubly fortunate (thanks to selfless naturalists like David) to be able to see and photograph many of the wonderful and varied species of the Orchid family and to be able to share them with you.

Until next time…

–Jim

12 comments


  • Virginia Craig

    Wow! Great pictures. And thanks for the background rundown. Hoping to see this someday in bloom.

    May 07, 2017
  • sonnia hill

    Wonderful history, range habitat and photos of this little orchid.

    May 07, 2017
  • Charles L. Argue

    Engaging account and remarkable photographs. Thank you.

    May 07, 2017
  • Michael Drake

    Great pix as usual. I hope all who read this are doing all they can to pressure our elected politicians to keep their thieving hands off the ESA and our wild lands. Our planet depends on us

    May 07, 2017
  • Penny Firth

    Fantastic! I would love to find these. I just discovered a population of the large whorled pogonia that was new to me.

    May 07, 2017
  • Smita Raskar

    Cute little orchid, Incredible pictures, Informative post

    May 07, 2017
  • John Fowler

    Great article.

    May 08, 2017
  • Lee Casebere

    Always a pleasure reading your interesting blogs, Jim, especially when it involves plants I’ve never seen. And, as usual, your photos are mighty fine!

    May 11, 2017
  • Fantastic photos – what a great trip!!

    May 13, 2017
  • Jane Ratterree

    Thanks for sharing.

    May 16, 2017
  • Ava Turnquist

    Beautiful photos! Thank you for sharing some habitat photos and a description. More habitat photos are always appreciated. A couple questions: Were there any white pine nearby? How about witch hazel? Were they in a runoff area? Were the located on a south or southeast facing slope? Thank you for sharing!

    May 18, 2017
    • Jim

      As one might expect to find in this higher elevation part of South Carolina, there are white pine in the area, but not in the immediate vicinity of the plants. As I mentioned, there were hemlock, but they are now dead for more than 5 years. The orchids are growing on a gently sloping flat area about 30 feet above the creek — not exactly what I’d call a flood plain, but something similar in make up. The slope is westerly facing. No runoff nearby, and there was the occasional witch hazel shrub, upslope.

      May 19, 2017

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