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Ohio’s Rarest of the Rare

Posted on 11/17/2014 by State Nature Preserves

Did you know that one in three of Ohio’s native plant species is considered to be rare within our state? Of the roughly 1,800 indigenous members of our flora, over 600 are currently listed as extirpated, endangered, threatened or potentially threatened by the Division of Natural Areas and Preserves. The reasons and/or cause for a species’ scarcity can be a wide ranging list. Habitat destruction, limited habitat availability, low genetic variability and being on the periphery of its natural distribution are but a few of the possibilities.

Small White Lady's Slipper

A large portion of my day-to-day work as a field botanist with the Division of Natural Areas and Preserves deals directly with these state-listed plants. Monitoring, surveying and managing their limited populations and ecosystems helps us better understand each species’ occurrence in our state and their future outlook. In this particular post I’d like to share a selection of Ohio’s most endangered and imperiled vascular plants, such as the small white lady’s slipper (Cypripedium candidum). This dainty spring blooming orchid only grows in a few high quality limestone barrens or tall grass prairie remnants and has quite an affinity for fire.

Lakeside Daisy

Some plants in our diverse state are not only rare in Ohio but everywhere else they occur as well. In special cases these species are additionally listed at the federal level as threatened or endangered. Here in Ohio, six different plant species fall into this category, including the magnificent lakeside daisy (Tetraneuris herbacea). These golden yellow beauties bloom en masse each May on the limestone quarries and historic alvars of the Marblehead Peninsula along Lake Erie and almost nowhere else on Earth. Additionally, only the Bruce Peninsula and Manitoulin Island in Ontario, Canada can boast extant naturally-occurring populations.

Appalachian Spiraea

Another federally listed rarity that calls Ohio home is the Appalachian endemic Virginia spiraea (Spiraea virginiana). Its habitat niche of gravel bars and scour zones along mid-sized streams makes it as unique as it is scant. Clusters of white flowers with conspicuous protruding stamens appear in July and are the envy and desire of countless insect pollinators. Virginia spiraea was first discovered in the state back in the early 90’s along Scioto Brush Creek and to this day is only known to occur in small, sporadic clonal patches along its pristine waters.

Canby's Mountain Lover

This next plant has often been given the distinction of being “Ohio’s rarest plant”, so it would only seem appropriate it make the cut here. Cliff-green or Canby’s mountain lover (Paxistima canbyi) is a low-growing, evergreen shrub only known from two dolomite limestone bluffs in southern Ohio; both fortunately located on protected land. The two sites are believed to be ancient clones leftover from the preglacial Teays River, a long extinct precursor to the present day Ohio River watershed. The Teays’ northwest flow out of the Virginias allowed many plants of the southeast to migrate along its main channel and tributaries with some like the cliff-green, flame azalea and aforementioned Virginia spiraea persisting in small pockets in Ohio to this day.

Painted Trillium

Many reading this may already know Ohio’s state wildflower is the large-flowered trillium (Trillium grandiflorum). This wide-ranging species can be found in nearly every county in the state and thankfully so. On the complete other end of the spectrum is its close brethren, the painted trillium (T. undulatum). This breathtaking wildflower only grows at one site in Ashtabula county in extreme northeastern Ohio. Heavy pressure from deer predation and a fluctuating climate could spell doom for our painted trilliums going forward but that’s the knife’s edge we walk with our rarest of the rare plants.

Ear-leaved Foxglove

For decades the ephemeral pink blooms of the fall-flowering ear-leaved foxglove (Agalinis auriculata) were feared to be gone forever from Ohio’s landscape. However, a chance discovery in the mid 80’s changed all that when it was found to be clinging to existence in the famed limestone barrens and prairie region of Adams County. Today, it’s still only known from a scattering of populations in the near vicinity of the original but with the careful management and attention its habitat receives, its future is considerably brighter.

Appalachian Filmy Fern

Hiding in the cool, moist and deeply shaded recesses of the Hocking Hill’s luckiest alcoves lives arguably Ohio’s rarest fern. The Appalachian filmy fern (Trichomanes boschianum) is a timid and fragile plant with parts of its fronds only a single cell thick! It grows from the ceiling of its sandstone homes with its roots anchored into fissures and cracks, feeding off the continuously percolating groundwater. Only a few very small and delicate clumps of the filmy fern are known to exist in the state despite plenty of seemingly hospitable habitat throughout the area. A point worth noting on this fern is the fact our populations are the northernmost known for its species; its next closest sites are located further south in Kentucky and West Virginia.

Wood Lily

It can be said that not all of Ohio’s rare plants are pretty and that not all our pretty plants are rare. However, the wood lily (Lilium philadelphicum) is unequivocally a case where both beauty and scarcity come together in perfect unison. Come June, their fire orange-red tepals seem to glow in the lengthening sunlight and are nigh on impossible to overlook. I’m hard pressed to think of a finer floral display to ring in the summer months. Currently, wood lilies are only known to be extant in select sites in extreme southern Ohio and the Oak Openings region in the northwest.

I consider myself to be very fortunate to get the opportunity to witness these great botanical rarities in their natural habitats. It’s an empowering yet humbling experience to be on the front lines of preservation in the constant battle to keep these precious gems of our natural world intact for future generations to enjoy and be inspired by. It would be a great loss for Ohio to see any one of the featured plants shared in this post disappear. I hope you enjoyed this brief exposure to some of the rarest of our vascular plants and were perhaps introduced to some species you didn’t even know existed. It’s certainly a wild and wonderful world out there, even in the Buckeye state!

Click To learn more about all the 600+ species of Ohio’s native rare plants.

Andrew Gibson