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Molecular Systematics

Phylogenetics of Plantaginaceae Tribe Gratioleae and the Genus Gratiola


This study evaluates the evolutionary relationships of the ca. 35 species of the plant genus Gratiola using non-coding chloroplast DNA sequences and morphology and provides hypotheses concerning the biogeographical history and evolution of morphological characters of this genus. Gratiola grows in portions of eastern and western North America, Central America, temperate South America, temperate Australasia, and Eurasia.   


Revision of Gratiola (Plantaginaceae) : A Genus of 35 Wetland Species With a Temperate Worldwide Distribution


 This study focuses on providing detailed taxonomic information for all 35 species of the genus Gratiola, a wetland group found in wetlands throughout the temperate portions of the northern and southern hemispheres. Each species is fully described, illustrated, and mapped, and notes concerning nomenclatural history, habitat, and conservation status are included. A dichotomous key is provided to differentiate all species. Two new species have been described from North America (one is G. quartermaniae, above right) and another five new species are being described from Australia and New Zealand (these are being investigated by grad student Rebecca Johnson). This study will be soon be submitted for publication to Systematic Botany Monographs

Asarum canadense Complex (Aristolochiaceae): is our eastern North American wild ginger a single species or three?


In this study, the morphological variability of the  common wild ginger of eastern North America was critically evaluated by examining herbarium specimens and studying natural populations throughout the eastern U.S. Preliminary findings indicate that what is currently considered one species should actually be recognized as three, morphologically distinct species, Asarum canadense, A. reflexum, and A. acuminatum.  

Taxonomy & Biogeography of the Meadow-Parsnips of Eastern North America, theThaspium barbinode Complex (Apiaceae)

This collaborative study with UT botanist, Dr. Eugene Wofford, examines the morphology of plants commonly known as meadow-parsnips. Prior to our work, botanists considered there to be one species from the Atlantic Coast to the Great Plains. Our study demonstrates that plants west of the Appalachians are distinct from those of the Appalachians and eastward (except for a few populations in the Midwest and Ozarks which likely represent glacial relicts). The western plants represent Thaspium chapmanii whereas the Appalachian-centered plants are T. barbinode. As part of this study we have also identified a new species of Thaspium that is endemic to the Allegheny Plateau of northeastern Kentucky. This new species will be described in the next year. 

Systematics of Clematis subgenus Viorna (Ranunculaceae)

This is a collaborative project with Aaron Floden (Univ. of Tenn.), Theo Witsell (Arkansas Natural Heritage Program), and Dr. Joey Shaw (Univ. of Tenn. Chatt.). The goal of this project is to prepare a full systematic revision of the North American species of Clematis subgenus Viorna. This group currently contains 16 species but our work indicates that there are between 6 and 10 new, undescribed species from the southeastern U.S. including new species from Texas, Arkansas, Louisiana, Georgia, and Tennessee. Our revision will present detailed morphological descriptions, updated habitat and distribution information, full illustrations with photos and line-drawings, and a molecular phylogeny.

Morphology, Ecology, and Biogeography of Polymnia canadensis (Asteraceae), A Widespread Species of Eastern Temperate North America


 Polymnia canadensis is a widespread species of the sunflower family found throughout eastern North America. Courtney Gorman M.S., recent graduate of APSU and now pursuing a PhD at the Univ. of Tenn. studied this group for her thesis and performed a detailed morphological investigation. She found that the species consists of several well-marked morphological extremes that may need to be recognized as distinct subspecies.

The Taxonomic Status of Viburnum bracteatum, A Rare Shrub of the Southeastern United States (Adoxaceae) With a Bicentric Distribution

This study, published in Castanea in 2010 (the Journal of the Southern Appalachian Botanical Society), focused on examining what botanists were considering two species in the shrub genus Viburnum. Populations in the Ozarks and Ouachita Mountains of Arkansas, Missouri, and Oklahoma had been recognized as V. ozarkense. Populations in southeast Tennessee, northeast Alabama, and northwest Georgia were recognized as V. bracteatum. This study demonstrated that these two species could not be distinguished based on morphology and that they actually should be treated as a single species - V. bracteatum


Carex fumosimontana : A New Species from Great Smoky Mountains National Park & The First New Plant Species Discovered Since the Beginning of the All Taxa Biodiversity Inventory (ATBI) Project


This study is being published in Brittonia, the Journal of New York Botanical Garden. It describes the discovery a new rare grass-like species, the Smoky Mountain Sedge (Carex fumosimontana), a new endemic from Great Smoky Mountains National Park. It is found only on the summits of two of the state's highest peaks, Clingman's Dome and Mt. LeConte and nearby portions along the Appalachian Trail of Tennessee and North Carolina. It grows in high-elevation mountain meadows and seeps among spruce-fir forest. Interestingly, this new species is the first plant to be described from Great Smoky Mountains National Park since the start of the All Taxa Biodiversity Inventory began. It has escaped detection in spite of being one of the most common species beneath the Clingman's Dome observatory, one of the most frequently visited sites within the U.S. National Park System.


Cumberland Rose Vervain (Glandularia sp. nov.) - A Beautiful New Endemic Species Restricted to the Cumberland River Valley of Tennessee and Kentucky

This study concerns the discovery of a new and beautiful species of Rose Vervain from the upper Cumberland River Valley of Tennessee and adjacent Kentucky. This species, pictured above right (note typical species at far right for comparison) differs in its much larger flowers and plant size, different leaves, and distinctly different habitat preferences.


Gratiola quartermaniae - A New Species Named in Honor of Dr. Elsie Quarterman, Pioneer of Cedar Glade Ecology & Retired Plant Ecologist of Vanderbilt University








A new species, Gratiola quartermaniae, was discovered and named in 2007 for retired Vanderbilt Plant ecologist, Dr. Elsie Quarterman (pictured above). Dr. Quarterman is now 101 and lives in Nashville. She is renowned for her work on the cedar glade ecosystem of the Southeast. Gratiola quartermaniae is endemic to the limestone glades and was named for her to honor her work on the cedar glades.


A New Species of Lysimachia (Myrsinaceae) To Be Named for One of America's Greatest Explorers, Meriwether Lewis

A new beautiful plant species was recently discovered by APSU botanists at the Meriweather Lewis National Monument along the Natchez Trace in Lewis Co., TN. This national monument is the site where famous Lewis & Clark Expedition co-leader Meriweather Lewis mysteriously died in 1809. Intensive studies over the past few years has revealed that this new species is found only in the eastern one-third of Lewis Co. and the southwestern corner of adjacent Maury Co. and nowhere else in the world. The common name of this new wildflower will be Lewis' Loosestrife. 

Penstemon kralii : A New Species From Alabama and Tennessee Named for Retired Vanderbilt University Botanist, Dr. Robert Kral

APSU botanists discovered a new species of beardtongue in April 2011 during a fieldtrip to a natural area just outside Huntsville, Alabama while in town for the 2011 Association of Southeastern Biologists conference. The new species, just named Kral's Beardtongue (Penstemon kralii) in the Journal of the Botanical Research Institute of Texas, honors Dr. Robert Kral (above right), professor emeritus of Vanderbilt University, who is one of the few to collect this new species and one of the most prolific botanists in the history of the southeastern U.S.

Polymnia johnbeckii : A New Species & One of the "Rarest" Plants in the Southeast Discovered Along Shoulder of Interstate 24 Just Outside Chattanooga, Tennessee

This new species was discovered unexpectedly 30 miles west of Chattanooga in 2008 and subsequently described in 2011 in Systematic Botany. It is known from only two populations in Marion County and nowhere else in the world and is one of the rarest species in the Southeast. It was named in honor of Chattanooga botanist, John T. Beck (pictured above right in the Rio Grande gorge in west Texas), now of Crescent City, Florida. 

The Rare May Prairie Aster, A New Species Discovered in Coffee County, Tennessee and Known Only from One Site Worldwide



In 2008 Dr. Estes discovered an unusual aster while leading a grass identification workshop for participants in town for the 2008 Natural Areas conference. The workshop was held at May Prairie State Natural Area outside Manchester, Coffee Co., TN - a site that is one of the undisputed crown jewels of the Tennessee Natural Areas System. This small prairie in The Barrens is home to nearly two dozen rare plants, including a couple not known from anywhere else in the state. Most of the rare plants at the prairie are disjunct from the pinelands of the Deep South. So, when Dr. Estes discovered an odd aster that he couldn't identify on that cool September day he figured it must be a rare species not previously documented from Tennessee that is found in south Alabama or Georgia. After consulting with Dr. John Semple of the University of Waterloo in Ontario, Canada it was determined that this odd aster was in fact a totally new species and its nearest relative is Symphyotrichum fontinale - known only from sandhills some 375 miles south in northern pensinsular Florida! This new species, to be called the May Prairie Aster, is presently a single-site endemic and has not found anywhere else. It is the dominant aster within the open prairie at May Prairie Natural Area where it can be seen from August to October.

Flora of Tennessee Project

The Flora of Tennessee project is a collaborative effort among several of Tennessee's botanists to write the first comprehensive "Guide to the Vascular Flora of Tennessee." This project is led by Dr. Wayne Chester, in collaboration with Dr. B.E. Wofford (Univ. of Tenn.), Dr. Joey Shaw (Univ. of Tenn. Chatt.), Claude Bailey (Jackson State Comm. College), Dr. David Webb (TVA), Dennis Horn (TN Native Plant Society), Aaron Floden (Univ. of Tenn.), and Dwayne Estes (APSU).  This book will be the state's first technical guide to the ca. 2,800 plant species (all ferns, wildflowers, grasses, trees, shrubs, and vines) found naturally in Tennessee and will become the standard plant manual for botanists, plant ecologists, naturalists, and field botany students in the state. The team will complete the first draft by Aug. 1, 2012 and will submit their book to the Univ. of Tennessee Press for publication in spring 2013. This projects comes on the heels of the 2009 production of the Fifth Checklist of Tennessee Vascular Plants published by BRIT Press which provides a comprehensive checklist of all known species of vascular plants in Tennessee (see above). 

Flora of the Ocoee River Gorge, Polk County, Tennessee

Since 2010, APSU and UT Chattanooga botanists and botany students have been involved in an intensive survey of the flora and vegetation of the Ocoee River Gorge in the Blue Ridge Mountains of Polk Co., Tennessee. Our study has documented 870 vascular plant species, including 26 rare species and two species new-to-science. We have also mapped the ecological systems of the Ocoee Gorge and have identified two new globally unique vegetation types. This study is being conducted as part of an environmental impact statement (EIS) to evaluate the impacts of a potential highway as part of the Corridor K highway project. This project is being conducted under contract with URS Corporation for the Tennessee Department of Transportation.

Flora of Rattlesnake Falls: A Potential State Natural Area on the Western Highland Rim Escarpment, Maury County, Tennessee

A botanical survey of Rattlesnake Falls and its surrounding ravines and hollows was conducted to determine the site's signficance as a potential state natural area. More than 620 vascular plant species were documented from the 100-acre study area, including numerous rare species, and Lewis' loosestrife a new species-to-science discussed above. This site has long been in private ownership and is a major conservation target. It represents one of the best ravine systems on the Western Highland Rim and is one of the most significant natural areas within south-central Tennessee.

Flora & Vegetation of the Cheatham Wildlife Management Area, Cheatham County, Tennessee

Recent APSU graduate, Clea Klagstad (now of the Montana Natural Heritage Program) studied the flora and vegetation of the 20,000 acre Cheatham Wildlife Management Area in Cheatham Co., TN. She documented approximately 600 plant species and mapped the plant communities of the WMA for her thesis. The training she received at APSU in botany and in GIS helped prepare her for an awesome career as a field botanist who now gets to enjoy working in the northern Rocky Mountains and Great Plains. 


Rare Plant Survey of the Obed River Gorge, Morgan County, Tennessee

APSU botanists, working under contract with the National Park Service's Obed Wild and Scenic River, performed an intensive survey for rare and invasive plants along 5 miles of the rugged Obed River in Morgan Co., TN. Their study resulted in the discovery of numerous rare species restricted to rare cobble bar habitats and resulted in the discovery of two new species to science that are awaiting description. This study also led to the realization tha the Obed River is severely infested with the aquatic invasive species Hydrilla verticillata. That discovery led to a subsequent study of the Hydrilla problem (see below).


Distribution, Abundance, and Habitat Preference of the Monoecious Hydrilla verticillata in the Emory River / Obed River Watershed, Cumberland and Morgan Counties, Tennessee

APSU botanists recently discovered that the Obed and Emory Rivers as Daddy's Creek, all streams on the northern Cumberland Plateau, are severely infested with the monoecious form of the aquatic invasive species Hydrilla verticillata. The goals of their study were to determine the extent of the invasion within the watershed, the habitat preferences of Hydrilla, and to locate the source of the infestation. It was discovered that the Hydrilla was originating from a private lake that drained into Daddy's Creek and that from this point it has spread more than 50 miles downstream through Daddy's Creek, the Obed River, and Emory River. The effects of this infestation are being evaluated by the Hydrilla Task Force, a group that formed in 2012 to determine what can be done to mitigate this problem and understand the potential impacts to the biota of the river system.


Vegetation of Tennessee

Dr. Dwayne Estes is working with the APSU GIS Center and his graduate/undergraduate students to map the natural plant communities and remaining significant natural areas of Tennessee. This work will help to better understand the status of many of the state's natural areas and to help direct conservation efforts. Dr. Estes is also working on a book titled The Natural History and Vegetation of Tennessee which will complement the mapping project and offer detailed descriptions of Tennessee's myriad plant communities.

Floristic Ecology Study of Limestone Glade Seeps of Kentucky and Tennessee

Recent APSU graduate, Kim Norton M.S., now botanist with the Botanical Research Institute of Texas in Fort Worth, studied globally rare wetlands (above) associated with limestone glade communities of central Tennessee and Kentucky for her thesis research. For her project, she documented the flora, rare plants, invasive species, and vegetation structure of these sensitive communities and provided evidence that these communities should be treated as wetlands in spite of their occurrence in near desert-like conditions in summer and fall. Ecologists with the US Geological Survey and US Fish and Wildlife Service are now consulting her thesis as they proceed with trying to understand the hydrology of these karst wetlands. 

Floristic Ecology Study of Calcareous Seepage Fens of the Western Highland Rim of Tennessee

APSU botanists are engaged in an ongoing botanical study of Western Highland Rim Calcareous Seepage Fen communities. Specifically, these communities are being intensively floristically surveyed and their vegetation structure and variation is being assessed. These small hillside wetlands are found in fairly rugged sections of western middle Tennessee in portions of Cheatham, Hickman, Lawrence, Lewis, Maury, and Williamson counties. 

Floristics and Vegetation of the Pennyroyal Plain Barrens, Kentucky and Tennessee

Dr. Wayne Chester, professor emeritus and former curator of the APSC Herbarium, has studied the Pennyroyal Plain barrens (also known as Big Barrens) of Kentucky and Tennessee for much of the past 40 years. He has collaborated on papers with Drs. Jerry and Carol Baskin (Univ. of Kentucky) to document the flora and vegetation of what was once one of the largest grassland systems in the southeastern U.S. Near the start of the 19th century this grassland stretched from Bowling Green, KY and Clarksville, TN west to the Ohio River. Early French explorer Andre Michaux and others noted the wide open prairies that burned nearly every year, the paucity of trees, and the presence of animals such as elk, bison, and prairie chickens (now long gone). Today, more than 90% of this grassland has been lost to agriculture and development and only a few thousand acres (none of which are virgin prairie) exist at nearby Fort Campbell Military Base. If not for Fort Campbell this globally-imperiled grassland system would have been lost long ago. Fortunately, however, the Fort Campbell remnants provide habitat for numerous rare wildflower species and songbirds (like Henslow's sparrow) found nowhere else in Tennessee or Kentucky.  

Flora and Vegetation of Baker Prairie, Dickson County, Tennessee

APSU senior, Rob Shepard, is working to document the flora and vegetation of a 13-acre barren remnant in Dickson Co. This site, known as Baker Prairie, has had a varied history and has been wooded and cleared, cultivated for crops, grazed by cattle, plowed, and bush-hogged. Today, however, it supports a remarkably diverse assemblage of native plants. Rob is documenting this diversity and the barren's present structure and hopes to work with the Baker family to manage the site with prescribed fire. Future APSU students will hopefully be able to document how the flora and vegetation structure changes as fire is restored this site.


Phytogeography of the Interior Low Plateaus Physiographic Province

Phytogeography is the study of plant distribution patterns. It is a branch of biogeography and is closely allied to phylogeography - the study of the distribution of genetic haplotypes across the range of a species. APSU botanist Dr. Dwayne Estes is collaborating with Bruce Sorrie (North Carolina Heritage Program), Dr. Alan Weakley (Univ. of North Carolina Chapel Hill), and Theo Witsell (Arkansas Natural Heritage Program) to characterize the dozens of plant distribution patterns for the unglaciated portion of eastern North America. This work will be an important contribution to our understanding of why species occur where they do and will lay the foundation for addressing how these species have moved over time in response to climate change, glaciation, and habitat migration.