RESEARCH OF DR. CHARLES HORN
Professor of Biology, Newberry College

RARE AND INVASIVE PLANTS OF SOUTH CAROLINA:  The flora of South Carolina has been studied for many years, yet there is still much to be discovered.  For, example Rhododendron eastmanii (May-white Azalea) has only recently been discovered (see photo below left).  As a result of field trips during 2001-2004, I have now documented 23 populations in South Carolina.  This is just one example of the need for field oriented investigations to further document and understand why some species are rare.  Toward this end, I have studied several rare species in South Carolina and published the results. 

In addition, many think that plant distributions are static.  Not so; many species migrate (spread) with time.  Some problems occur when species are introduced from other continents and subsequently spread.  Some well known examples in the South Carolina are kudzu and Japanese honeysuckle.  Recent more recent examples include the mariana fern (photo below right), and Japanese stilt grass.

Rhododendron eastmanii (May-white azalea), an endemic of central South Carolina.  It was first described as a new species in 1999 by Kathy Kron and Mike Creel.  Photo by Charles Horn, May 2008.

Macrothelypteris torresiana, a fern introduced into Florida many years ago and has recently been documented as spreading in the piedmont of South Carolina.  Plants grow along streambanks in woodlands.  Photo by Charles Horn, July 2004.

NEW HYBRID SPECIES IN SOUTH CAROLINA:  Over the last two years I have been working on a potential new hybrid of pawpaw (genus Asimina). You might even know the pawpaw song?? This group of species is well know for producing edible fruits, but little is known of populations in the wild.  I have been studying several populations of pawpaws that appear to be a hybrid between the common pawpaw (Asimina triloba) and the dwarf pawpaw (Asimina parviflora).  With the assistance of several students, we have investigated leaf size, flower size and soils.  A group at Wingate University is in the process of completing DNA analysis.  Details, including pictures can be seen by clicking here. 

FLORA OF SOUTH CAROLINA: As we look at the diversity of plants we see an equal diversity of distribution patterns.  Some species are widespread, while others are resreicted to a narrow area (botanists use the term endemic to describe the small area of distribution).  Botanists have been gathering information on each species distribution for many years. So some botanists spend their time looking a specific species (see above).  Another approach is to look at a specific area and determine, through repeated visits, the flora of that area.  I have completed such a project for Lynch's Woods Park (Newberry County) and Saluda Shoals Park (Lexington County).  This last year Ihave initiated a new project at the Enoree Rich Woods area of the Sumter National Forest (Laurens County) and this year I am working on a flora of Little Mountain (Newberry County).  Student assistance on field trips is always welcome.

The tulip tree (Liriodendron tulipifera), is a common forest tree of South Carolina and has been documented in essentially every South Carolina county.  Photo by Charles Horn, May 2008 at Lynch's Woods Park, Newberry County.

Eurybia mirabilis (piedmont aster) is a rare species known only from North and South Carolina.  Photo by Charles Horn, August 2008 at Lynch's Woods Park, Newberry County

FAMILY PONTEDERIACEAE (pickerel-weed Family):  This is my doctorate ressearch area that I have continued to work on over the years.  My primary research interest continues to be with the systematics and ecology of the Pontederiaceae, a monocot plant family known as the pickerel-weed family, the subject of both my masters and doctorate research projects.  Species of this family are widespread, especially in the new world tropics and subtropics.  In addition, some species are know from Africa and Asia.  One species, Monochoria cyanea, is native to Australia.  Several species have been introduced as weeds into Europe and Australia, including one of the worst weeds, Eichhornia crassipes (water hyacinth).  My master's thesis and doctorial dissertation related to the genus Heteranthera, the mud-plaintains.  I have put together a number of publications relating to the Pontederiaceae.

Heteranthera dubia (water-star-grass), as seen from a boat in Ducker Bay, Mobile River.   These plants are of a long perianth tube form only known from along the Gulf Coast from Alabama to mexico.  Photo by Charles Horn, 1981.

Heteranthera oblongifolia, as grown in my backyard.  The seeds are originally from Alagoas, Brazil.  This species produces two flowers per inflorescence and the perianth lobes never open more than to a 45 degree angle.  Photo by Charles Horn, June 2008.

This page last updated 15 September 2009 | to Dr. Horn's homepage