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FLORA OF THE CAROLINAS AND VIRGINIA

Working Draft of 1 January 1997 by Alan S. Weakley

The Nature Conservancy Southeast Regional Office Southern Conservation Science Department

Mail: 101 Conner Drive, Suite 302, Chapel Hill, North Carolina 27514 Telephone: 919-967-5493 ext. 128 Fax: 919-967-1575 E-mail: aweakley@tnc.org

(copies by permission of the author only)

INTRODUCTION

The understanding of the flora of the Carolinas and Virginia has progressed substantially since the publication nearly thirty years ago of the landmark Manual of the Vascular Flora of the Carolinas, by A.E. Radford, H.E. Ahles, and C.R. Bell. Many additional species have been documented as part of the region's flora, additional alien species have become naturalized, new species have been described, monographs have given new taxonomic insights into groups, nomenclature accepted in 1968 has been found to be invalid, new and more reliable keys have been developed, and systematic treatments have advanced. Increasingly, identification of the flora of our area (and other states of the Southeast and Mid-atlantic) by academic researchers, agency personnel, and advanced amateurs is hampered by the lack of an up-to-date flora. Without such a flora, identification must involve reference to herbaria and thousands of monographs, papers, and other floras -- resources not readily available to most people who need them. The absence in the region of a modern standard for the systematic treatment, nomenclature, and identification of the flora compromises scientific studies, ecological research, and agency inventory, management, and monitoring of ecosystems and rare species.

I intend this new flora for the Carolinas and Virginia to fulfill part of the need, until a thorough revision of the Manual is feasible. The emphasis of the Flora is on workable and detailed keys to all taxa, emphasizing vegetative characters where possible (to extend the period of the year in which species can be identified), detailed description of known habitats in the 3-state region, additional characters or hints useful in discrimination from similar species (including species not closely related but superficially similar and therefore confused), reference to the body of recent literature various aspects of the flora of our area, and discussion of abundance, phytogeography, and ecology. Our knowledge of the flora of our region is far poorer than is generally recognized, and past floras have sometimes contributed to this impression, by obscuring taxonomic judgments or "lumping" poorly known taxa. An attempt is here made to draw attention to taxonomic questions or controversies, while at the same time presenting (as best as possible) a useable, current, consensus treatment. In making taxonomic decisions, I have generally relied strongly on recent monographs and revisions and the checklist of Kartesz (reviewed by hundreds of experts), but have tempered published treatments with field knowledge, examination of herbarium material, and consultation with other botanists in the region. While reluctant to disagree with recent monographs (by authors who have studied the groups in more detail than I have), I have also attempted to impose a somewhat consistent concept of taxonomic categories (family, genus, species, subspecies, and variety), so as not to have a very uneven treatment, with some genera divided finely and others coarsely.

The geographic scope of the Flora is Virginia, North Carolina, and South Carolina. The three recent atlases of the Virginia flora (the most recent being Harvill et al., 1992) have done much to elucidate the state's flora, and to encourage a new wave of floristic exploration. The addition of the state of Virginia to the geographical scope covered by Radford, Ahles, & Bell offers a number of advantages. The three-state region is a compact and relatively natural unit; Virginia, with its strong representation of Southern Appalachian and southeastern Coastal Plain species, has stronger floristic affinities to the Carolinas than to states to its north and west, with which it has often been treated in the past (as in Fernald, Gleason & Cronquist, etc.). The three-state coverage will provide botanists working primarily in one state with a greater regional perspective, and should promote an increased knowledge of each state's flora, by making readily available information on species nearby.

The concept that floras should be "conservative" (i.e. should take a "lumping" approach) strikes me as dangerous. Horton (1972), for instance, states "manual treatments in general should be conservative, leaving the fine points of distinction among taxa, especially infraspecific ones, to the monographer." Floras become the standard used by the great majority of users in an area, and taxa that are "lumped" are lost to the conciousness of all botanists other than a few specialists. Thus, two parallel taxonomies are established, one in common use and one (based on the best judgments of experts in the groups) not used, except by a few, interested in (and able to) seek out the papers of specialists. Ecological studies, species lists for parks or natural areas, rare species surveys, and assessments of the ecological significance of potential conservation areas are all flawed if not based on the best current information available. Moreover, from the standpoint of information theory and information management, a species list using a "lumped" taxonomy has lost information; if a "split" taxonomy has been used, the information is retained.

Even a casual perusal of the synonymy listed under the species of nearly any substantial genus in our flora will reveal taxa that have been variously treated as species, infraspecific taxa (variety or subspecies), and included within another taxon. Further studies, sometimes based on different techniques, sometimes simply by a different taxonomist with a different taxonomic philosophy, often result in the overturning of a previous taxonomic judgment. The basic categories of our taxonomy still do not have generally accepted, consensus definitions and criteria. With the taxonomy of our area still in such flux, I am inclined to provisionally accept some infraspecific taxa (or at least mention their alleged characters in the discussion under a species) so that they are not "lost in the shuffle."

The problem of the infraspecific categories variety and subspecies is a vexing one. A recent study of current practice in the use of various infraspecific categories showed that the usage of variety and subspecies was profoundly muddled, with regional traditions as important as taxonomic philosophy in determining usage (Hamilton & Reichard 1992). Anderson, Crum, & Buck (1990), in a recent checklist of North American mosses, concluded "we have been unwilling to list both subspecies and varieties because the differences between them are not clear to us. As far as we can judge, a subspecies and a variety are the same thing. The varietal designation has long been used in botany, more specifically in bryology, and we see no particular gain, at least at this stage of our knowledge, in attempting to erect more than the single infraspecific category, variety". Holmgren (1994) has also presented a strong argument for use of the varietal rank. While I strongly agree with this sentiment, standardizing all infraspecific taxa recognized in our area to either variety or subspecies would involve hundreds of new combinations; such proliferation of combinations (not based on new knowledge of the taxa) seems undesirable, though such an approach was taken by Dorn (1988) in the considerably smaller flora of Wyoming. For now, I am primarily using variety where choices exist, but accepting subspecies where an equivalent variety name does not exist. Occasionally (following recent monographers), I have accepted subspecies as an infraspecific category indicating a more distinctive taxon than variety. This is not a happy solution, since it means that the categories of subspecies and variety are not used consistently to indicate a different level of taxonomic distinction. I have been disinclined to use quadrinomials, as, for instance, Chamaecrista nictitans (Linnaeus) Moench ssp. nictitans var. aspera (Muhlenberg ex Elliott) Irwin & Barneby, because they generally strike me as unwieldy, impractical, and unnecessarily confusing, without providing sufficient compensating benefits (our state of knowledge rarely warranting or supporting such finely distinguished classifications of relationships).

In general, the user or reader will find the following general differences in taxonomic treatment, as compared to other floristic treatments of the area, such as Radford, Ahles, & Bell (RAB), Fernald (F), Gleason and Cronquist, 1st and 2nd editions (G, C), Small (S), Godfrey & Wooten (GW), the treatments so far published as part of the Vascular Flora of the Southeastern States (SE), Kartesz (K), Wofford (W), and Harvill et al. (H). Family level taxonomy generally follows Cronquist's recent work (reflected in C and K), with a few groups split more finely; this represents a generally somewhat finer splitting than RAB, F, G, GW, W, and H, substantially coarser than S. Generic level taxonomy has for the last several decades been generally headed towards finer divisions; this treatment reflects that trend, with genera split somewhat more than RAB, F, G, W, and H, about the same as C, GW, K, and SE, and (of course!) more coarsely than S. It is interesting to note, though, that our generic concepts are now perhaps about halfway back to Small and Rydberg! At the species level, the treatment is about equivalent to C, K, and SE, slightly more finely split than F and G, substantially more finely split than RAB, GW, H, and W, and substantially coarser than S. Infraspecific taxa are recognized much more frequently than RAB, H, and W, somewhat more frequently than GW, about the same as C, G, K, SE, and much less frequently than F (probably less than half of Fernaldian varieties are recognized at any level). S did not use varieties (except very exceptionally); many taxa recognized by S as species are here regarded as varieties, or not recognized at all. Overall and on average, substantially more taxa are recognized than are by RAB and H, slightly more than by C, G, GW, W, about the same as K and SE, and substantially fewer than by F or S.

The Flora is being prepared as time allows. Drafts of family and genus treatments are being made available to interested botanists for use and field-testing. Some treatments must be considered tentative until further testing in the field and herbarium can be accomplished. All treatments should be considered as works in progress at this time, likely to change slightly or greatly before publication. For some species, determination of the distributions, habitats, and phenology requires additional herbarium and field work, not yet completed. I welcome suggestions on format and content.


PROGRESS (as of 1 January 1997)

Working drafts completed of: 177 families, 1055 genera, 3604 species or infraspecific taxa.

Estimated totals in NC-SC-VA: 225 families, 1174 genera, 4500 species or infraspecific taxa.

Percentage complete: families (78.7 %), genera (89.9 %), species (80.1 %).


CONTRIBUTORS

Richard J. LeBlond -- Cyperaceae: Rhynchospora, Scleria. Melastomataceae. Poaceae: Dichanthelium, Panicum. Zack Murrell -- Cornaceae. John B. Nelson -- Lamiaceae: Stachys. Robert K. Peet -- Juglandaceae: Carya (with A.S. Weakley). Milo Pyne -- Solanaceae: Physalis. Bruce A. Sorrie -- Asteraceae: Pityopsis. Cistaceae: Lechea. Cyperaceae: Carex (with T.F. Wieboldt and A.S. Weakley). Gentianaceae: Sabatia. Haloragaceae: Myriophyllum (with A.S. Weakley). Lamiaceae: Lycopus. Poaceae: Sphenopholis. Violaceae: Viola. Brian van Eerden -- Juncaceae: Juncus. Thomas F. Wieboldt -- Cyperaceae: Carex (with A.S. Weakley and B.A. Sorrie).


ACKNOWLEDGMENTS

Reviews, comments, contributions, and support have so far been gratefully received from the following: Jame Amoroso, Lewis Anderson, Loran Anderson, Matthew Barnett-Lawrence, Rodney Bartgis, Allen Belden, Millie Blaha, Marj Boyer, Ted Bradley, Richard Broadwell, Margit Bucher, Julian Campbell, Jay Carter, Roy Coomans, Bob Dellinger, Wilbur Duncan, Mary Felton, Gary Fleming, Chick Gaddy, Kancheepuram Gandhi, Bill Gensel, Bob Godfrey, Tom Govus, Ben Hafer, Jim Hardin, Karin Heiman, Hal Horwitz, John Kartesz, Benson Kirkman, Bob Kral, Julia Larke, Richard LeBlond, Harry LeGrand, Chris Ludwig, Jim Massey, Jim Matthews, Bob McCartney, Julie Moore, Mike Moore, Larry Morse, Bill Moye, Nora Murdock, Zack Murrell, Robert Naczi, John Nelson, Cary Norquist, Shawn Oakley, Doug Ogle, Tom Patrick, Karen Patterson, Linda Pearsall, Bob Peet, Dan Pittillo, Bert Pittman, Milo Pyne, Al Radford, Tom Rawinski, Doug Rayner, Mary Russo, Mike Schafale, Alan Smith, Inge Smith, Bruce Sorrie, Dave Taylor, John Thieret, Brian van Eerden, Donna Ware, Tom Wentworth, Peter White, Tom Wieboldt, Donna Wright, Steve Young, the Conservation Science Department of the Southeastern Regional Office of The Nature Conservancy, the North Carolina Natural Heritage Program (Division of Parks and Recreation), the Virginia Division of Natural Heritage, the Conservation Trust for North Carolina, and the NCU, NCSC, DUKE, UGA, VDB, FSU, BOON, WCUH, and UNCC herbaria.

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Flora of the Carolinas and Virginia, Working Draft of 1 January 1997 -- INTRODUCTION