Rare Plants in a Secret Prairie

This certainly isn't my first blog post to tell a tale of Adams county's ancient and mystical prairie openings and I can guarantee it won't be the last.  It's hard to stay away from such a diverse and engaging subject of Ohio's natural history and flora, especially when one spends a large amount of time combing its varying landscape.  Autumn is just as good a time as any during the growing season to visit the area's globally rare ecosystems and habitats, as they are still well alive with some of the year's last firework displays of wildflowers and tall warm-season grasses.  Come September I am always excited and anxious to pay a visit to one specific little prairie opening out of the hundreds of others to see one of Ohio's rarest vascular plants.

A particular Adams County limestone prairie with an elusive inhabitant 

At first glance this place doesn't seem to be anything different from the other countless dolomite-limestone barrens the county is widely famous for and you'd be right if you didn't know what to look for.  The rocky patches you see in the photograph above are not chunks of rock resting on the surface but rather exposed bedrock laid down over 400 million years ago during the Silurian age and known to geologists as Peebles-Dolomite.

Patch of exposed Peebles-Dolomite bedrock over 400 million years old

In many places the topsoil is only a few inches deep, making for very rugged conditions for any plant to grow in.  The soil is a type called rendzina, which is derived from weathered limestone bedrock and rich in humus, usually indicating an area that has been occupied by a grassland habitat for an extended period of time.  As time goes by and organic material builds up through decomposing plant matter, the soil becomes richer and comprised of more humus and less rock since the bedrock is slowly being covered and lost to the past.  Deep, rich soil is typical of mature forests that have had centuries, even millennia of leaf and herbaceous  decay but not so in these prairies where the organic soil layer is thin and bedrock still at the surface.  Despite the harsh reality of this environment, life has found a way to eek out an existence and cling to the shallow, rocky soil.  One of those survivors is the feature of this post and one of the most rare members of our flora.

Ear-leaved Foxglove  ~  Agalinis auriculata

Mixed in among the big bluestem (Andropogon gerardii), indian grass (Sorghastrum nutans), and little bluestem (Schizachyrium scoparium) lies the ear-leaved foxglove (Agalinis auriculata), a member of the figwort family (Scrophulariaceae).  A frequently used Latin synonym  for this species is Tomanthera auriculata.  Each September these plants grace this select prairie opening with their stunning pinkish-purple flowers for a couple weeks before slipping back into obscurity.

Ear-leaved Foxglove  ~  Agalinis auriculata

At first glance it's not hard to see the resemblance to other members of the Agalinis genus and its false-foxglove brethren.  The pink colored, five-lobed tube-like corollas appear in the leaf axils along the top of the stem.  Each flower only lasts a few hours before wilting and falling from the plant at the slightest touch or breeze. The buds break early in the morning and by noon are pollinated and have served their purpose for the day.  Each plant will bloom over the course of a week or so with a new set of flowers each morning until the ovary is fully fertilized and begins to mature.

Ear-leaved Foxglove  ~  Agalinis auriculata

Once pollinated the ovary quickly swells into a capsule tucked away inside the calyx and contains numerous small seeds.  The seeds mature quickly and are dispersed in late fall to over-winter and sprout in the spring.  Ear-leaved foxglove is an annual so seed production is a vital component to its continued existence and success; every plant, no matter the size, is the result of one season's growth and must complete its life cycle in that one  growing season.  A helpful trait this species has evolved to utilize is to be semi-parasitic on the roots of other nearby plants, most specifically asters (Symphyotrichum spp.).  The leaves are oppositely arranged and sessile with the upper leaves having two small lobes at the base where each leaf meets the stem.  These small lobes (auricles) or 'ears' are how the plant gets its common name ear-leaved foxglove and scientific epithet auriculata.

Ear-leaved Foxglove  ~  Agalinis auriculata

Due to being an annual, the plants put all their strength and energy into that one and only shot at flowering before giving up its ghost.  This leads to interesting results in the variation of size in flowering plants in a population.  I unfortunately caught these a bit late in the process this year and a large majority of the plants were already done and in seed but a few were still giving it one last go.  Some plants were eclipsing three feet in height and had multiple branching sections with dozens of seed pods on them while others, like this miniscule specimen above, were barely five inches tall with one bloom.

Distribution map of Agalinis auriculata (courtesy: BONAP)

The relic prairie I was standing in was just one of a handful of populations left of the ear-leaved foxglove in the state of Ohio.  The few others are well-kept secrets and scattered around the nearby area in other similar barren situations.  The original range for this species in Ohio was slim and scattered to begin with with the only records coming from Adams, Butler, Muskingnum, and Ottawa counties.  For decades the species was considered extirpated from the state and feared gone forever until a chance re-discovery in an Adams county prairie in 1985.  It had sat in the seed bank for an unknown amount of time before the right environmental conditions allowed germination.  Despite additional searching in Ottawa county, the species remains only extant in that handful of Adams county populations.  All the currently extant locations seem to be associated in one way or another with recent disturbance to the habitat, which is known to help stimulate the seed bank and allow this plant to spring forth.  Sometimes mankind's activities can have positive effects, even on something so rare as Agalinis auriculata.

Looking at the overall distribution and range of the species above shows a clustering in the 'breadbasket' region of the United States and outlying scatterings throughout the Midwest and south-central states.  Despite a good showing of records in those heartland states, many, actually most, of those counties no longer contain any existing populations of the ear-leaved foxglove.  Its affinity for mesic, rich, black-soiled tall grass prairies spelled its own doom when they were tilled and plowed for agriculture.  Today the ear-leaved foxglove is only found in about half of its original range with a majority of the remaining populations at the center of its distribution in Illinois, Iowa, and Missouri.  In response to its rarity and disappearing habitat due to succession and development/agriculture, this species is currently under consideration for federal listing.

Ear-leaved Foxglove  ~  Agalinis auriculata

There's something sentimental about being in the presence of something so beautiful and sparse.  It gives you a better appreciation for its existence and place in the natural landscape of these already special and rare ecosystems.  Apart from being the rarest denizen of this particular dolomite prairie, it was certainly not the only uncommon or charming plant to be found.  This next one is not only stimulating to the eyes but to the olfactories as well and can be found if you follow your nose...

Great Plains Ladies-tresses  ~  Spiranthes magnicamporum

I've shared the great plains ladies'-tresses (Spiranthes magnicamporum) on here before and it would seem rude to leave them out here when they are growing just a few feet away from the ear-leaved foxgloves and blooming concurrently.  As mentioned above, the odor emitted from these small crystalline flowers is deliciously sweet and refreshing and well worth a whiff.  It's not uncommon to smell these before you see them on a warm fall afternoon.

Great Plains Ladies-tresses  ~  Spiranthes magnicamporum 

One of the last species of orchid to bloom in the state, these plants are right at home in the xeric and calcareous thin soils of the dolomite prairies.  Spiranthes magnicamporum was once lumped as a variety of the infamously difficult Spiranthes cernua  complex.  In-depth research into its genetics, habitat, and phenology in the mid 1970's allowed the species to be rightfully elevated to full species status.  Its later blooming period, yellow-colored throat, strong fragrance, and dry, limestone habitat preference help separate it from the similar multiple forms of S. cernua.

Great Plains Ladies-tresses  ~  Spiranthes magnicamporum

A closer inspection of the individual inflorescences shows the lateral sepals flared away from the sides and raised just a bit above and seem to imitate the look of a charging bull.  The great plains ladies'-tresses begin to bloom in mid-September and are known to flower through October and into November after even the asters and goldenrods have called it a year.  It's hard to look at one of the last, if not the last, of the orchids to bloom and say goodbye.  For someone as passionately obsessed with that family as your blogger it's a bittersweet moment.

Great Plains Ladies-tresses  ~  Spiranthes magnicamporum

As I picked myself up off the ground from my low and close-up encounter with the great plains ladies'-tresses and dusted myself with crossed fingers the notorious chigger mites hadn't gotten me too bad, I took a look around the rest of the prairie and noticed some of the other interesting flora the habitat had to offer.  One of those quick to catch the eye was one of Ohio's only native succulent plants.

False Aloe  ~  Manfreda virginica

The fleshy, aloe-like leaves of the appropriately named false aloe (Manfreda virginica) are perfectly adapted to the dry and rough conditions of the drought-like barrens.  The tall flowering stalks waved in the breeze three to four feet above the leaves with their marble-sized seed pods turning black with maturation.  They flowered months ago in the heat and humidity of July and only have their unique leaves to show off come fall.

Rough Blazing Star  ~  Liatris aspera

Normally a well-welcomed and loved late wildflower, the rough blazing star (Liatris aspera) can become a potential downer when it's easily confused with the ear-leaved foxglove as you approach and gaze out into the grasses.  Other than the similar pink color to the flowers there's not much else to confuse the two with once getting closer to the plant.  I love all our native Liatris species but this one may be my favorite of them all.

Prairie Brome  ~  Bromus kalmii

Perhaps not the showiest or most noticeable of the plants there, the prairie brome (Bromus kalmii) deserves a closer look if for anything to see the fascinating wooly pubescence on the fruiting heads (spikelets).  Switching to the macro lens and focusing in on the lemmas and glumes reveals the interesting pattern and made for an artistic shot that turned out pretty well in my opinion.  Prairie brome is an uncommon species in Ohio and is at the southern fringe of its natural range, especially as far south as Adams county.

Prairie Orange Coneflower  ~  Rudbeckia fulgida var. fulgida

Despite peaking a couple months back in late July and early August, the prairie orange coneflower (Rudbeckia fulgida var. fulgida) was still holding on in pockets throughout the xeric landscape.  The small, deep-orange flower heads really add a spark of color and contrast to the light yellows and greens of the dominating grasses.  I look forward to publishing a post on all of Ohio's native Rudbeckia species in the near future.  They are one of my favorite genera of plants and are still a bit of a taxonomic mess.

Gray Goldenrod  ~  Solidago nemoralis

Probably the most common non-graminoid plant in the barrens was the gray goldenrod (Solidago nemoralis), a frequent and widespread species throughout the state in all sorts of dry soil situations.  It has the typical and classic goldenrod look but can be told apart relatively easily unlike a number of species.  It's short stature and unbranched,  wand-like appearance combined with a very pubescent grayish-red stem help with an ID.

With fall's climax fast approaching a gradual slip into the dull browns and grays of winter in the inevitable future I'm enjoying every second I can spend out in the field in the midst of the season's last botanical beauties and friends I won't be seeing for quite some time.  It's hard to believe another growing season is coming to an end; I swear I was admiring trillium and Virginia bluebells just the other day...