Small Whorled Pogonia

I have a client that requires a rare, threatened and endangered (RTE) plant species survey, and which specifically requires that we survey for the federally threatened and Virginia and Maryland endangered (highly state rare) small whorled pogonia (Isotria medeoloides).  Similar looking plants include the large whorled pogonia (Isotria verticillata) and Indian cucumber root (Medeola virginiana).


We have several field days to perform the survey on an extensive tract of land, and we have been preparing an all species list that will be incorporated into a larger natural resources management plan.

The best time to survey for small whorled pogonia is when it is at peak bloom, which for our Virginia site is mid to late May.  To prepare for this portion of the survey and calibrate ourselves, we visited an adjacent reference location, and I photographed this series of small whorled pogonia photos.  The pogonia was at peak bloom on May 15, 2015, and with our formal pogonia portion of the survey being performed on May 15, 18 and 19.


Our work site exceeds 130-acres of woodlands, and I’ve been on-site four days thus far during the early spring growing season.

Virginia DCR, Division of Natural Heritage has a document entitled the Natural Communities of Virginia:  Ecological Groups and Community Types.  Working through the community types, my site may be Piedmont / Coastal Plain Oak – Beech / Heath Forests, Acidic Oak – Hickory Forests, Oak / Heath Forests and/or Mesic Mixed Hardwood Forests.  Because of my all-species list, each time I go out, I’m able to better refine the primary forest type(s) that I am in, and I do have several signature species associated with small whorled pogonia.


We have been seeing Indian cucumber root with regularity, which will stop you in your tracks, as it can look similar to the small whorled pogonia.  This is a photo of Indian cucumber root prior to flower, taken from our site on May 6, 2015.


This is a photo of the exact same Indian cucumber plant in flower on May 15.


Small whorled pogonia is considered the rarest orchid east of the Mississippi.  The majority of its populations typically number fewer than 25 plants.  The primary threats to the pogonia are trampling, herbivory by deer and dense canopy closure.


According to the U.S. Fish & Wildlife Service, this plant is so rare that only approximately 104 populations are known, with a likely total of 5,000 plants.  Virginia, along portions of the I-95 corridor is a known national “hot-spot” for the pogonia.


The specific location of the small whorled pogonia was a relatively mature, mixed oak and beech forest.  You can see the brown color of beechdrops (Epifagus virginiana) to the right of the pogonia in this photo.


Plants may live for several years, and may also remain dormant for several years at a time.  Taller plants with larger whorl diameters tend to flower more frequently than smaller plants.  Flowers last about one week, if they should flower.  A colony will tend to flower at the same time at a given site.


Somewhat nearby the pogonia, we observed a sizable aggregate of pink lady slipper orchid (Cypripedum acaule), with likely eighteen to twenty plants, and with nine in flower.  I’d say that the peak bloom for the pink lady slipper was around May 10.


A striking and beautiful wildflower.  This colony was quite robust.


Moving on to our work site, we discovered four showy orchid (Galearis spectabilis) that were likely at peak last week.

So far we have 207 plant species on our list, and anecdotally we have directly observed spotted salamander, worm snake, five-lined skink, wood frog, ground hog, fence lizard, gray tree frog, spring peeper, house mouse, whitetail deer (too many), red-backed salamander, raccoon, eastern gray squirrel, eastern box turtle, red fox, turkey and snapping turtle.


This afternoon we documented four orchids nearby each other that all had a pair of basal leaves.  The one plant that was in bloom was growing through a leaf and was compressed, as the leaf acted like a band.  As soon as I pulled the dry leaf apart from the growing plant sheath, the orchid sprung out like an accordion.


Using Newcomb’s Wildflower Guide, we determined the plant to be large twayblade (Liparis lilifolia).  Given another day to expand, the spidery flowers would be more showy and fully formed.


This northeast native orchid is considered uncommon, and is State rare in Maryland and points north.  The flowers have a faint carrion (dead meat) odor, and that’s why the flowers mature to be a maroon red, taking on the color of meat.  The plant is pollinated by flesh flies.


Working through the woodlot, we noticed an adult male five-lined skink (Plestiodon fasciatus). 


When you think of a five-lined skink, you generally think of the classic five-lines and blue body and tail.  Females have a tendency to retain that color pattern, but the males “brown-out” with maturity and usually retain vague traces of stripes.  They will also express a red-colored head during breeding to enhance their attractiveness to the opposite sex.


Male five-lined skinks can be confused with the larger broad-head skink.  The way to confirm the difference is that broad-heads have five labial scales and the five-lined has four labial scales along the upper lip, between the nose and eye.  I had to enlarge a photo and do a count, thus verifying that these photos are of five-lined.

If you do a word search for broad-head skink on my blog, you will find a previous entry, where I have close-up photos of the larger broad-head skink, from a site along the Potomac River in Montgomery County, Maryland.


Wild Comfrey (Cynoglossum virginianum) is an uncommon late spring native of the northeast.  This plant can grow to two-feet tall and has large leaves that clasp onto a hairy stem.  The plant is also known as dog tongue, as the large leaves look like a dog’s tongue after having played hard, and hanging long-out of the dog’s mouth.


A close-up of the wild comfrey flowers.  This plant is at risk in New Jersey and Pennsylvania.  Note the hints of blue within the white flower.


Pointed Blue-Eyed Grass (Sisyrinchium angustiflorum) was a common sighting in the more open grassy patches of the forest edges.  I took this particular photo because this specific flower was a darker blue that the difference of the colony that all had a more sky, Carolina blue color.


Partridgeberry (Mitchella repens) was also rather common on our work site, and was at peak bloom.  This native perennial has a woody trailing vine and the small fragrant flowers have four petals with a funnel-shaped tube, fringed with hairs.  Spotted wintergreen (Chimaphila maculata) was also common on-site, and which looks like it will flower in the last week of May and into the first week of June.


We had significant thickets of mountain laurel (Kalmia latifolia).  Dense stands of laurel are known as Laurel Hell’s, as they can be nearly impenetrable, and one is forced to walk around them.  Deer are known to hide in Hell’s to prevent detection.  I love the ten anthers of each flower, which are spring-loaded, and fire-off a sticky packet of pollen onto insects when touched.  Great dispersal mechanism.


Cranefly orchid (Tipularia discolor) is quite common on our study tract.  This northeast native is rare in Pennsylvania, and all native orchids are special.  Cranefly orchid grows one single leaf in September, which then overwinters, and disappears in late spring.  The orchid flowers will rise from a single stalk in late July, and which are pollinated by moths.


This is a photo of rattlesnake plantain (Goodyera pubescens), an orchid that has striking leaves marked with a network of silvery veins and a broad stripe down the center.  This semi-evergreen plant is attractive year-round, and individual leaves can last three to four years.

We have been able to confirm six species of orchid from our job-site, including large twayblade, pink ladyslipper, rattlesnake plantain, large-whorled pogonia, cranefly orchid and showy orchid.  I’ve taken several photos of other possible orchid species, which were not in bloom, but only of leaves, which do not look like species that we have seen in flower.  I am therefore suspicious that we may have another orchid species or two on-site.


Now for the highlight of our survey, the uncommon large whorled pogonia (Isotria verticillata), which was post bloom and going to seed.  We think that the plant may have been at peak bloom in the latter part of the first week of May.  We found a total of twenty individuals in a loose aggregate colony, on a western facing forested slope.


This blog entry shows photos of the small whorled pogonia, Indian cucumber root and large whorled pogonia, all looking somewhat similar.  Note that the large whorled pogonia has a well defined purple stem, whereas the extremely rare small whorled pogonia has a green stem, with bluish green leaves.

Great days in the field.  Thank you to Tim, Leslie, Meegan, Neil, Tony, Nick and Catey for your assistance through these three days.


3/16/17.  Smithsonian Institution scientists in Maryland have discovered what triggers the rare small-whorled pogonia to awaken from dormancy.



5/7/17.  The following is a well done article and photo essay on small whorled pogonia: