Aquatic and Wetland Plants of Southeastern United States: Dicotyledons

Introduction

Introduction The aim of this work is to aid in identifying native and naturalized dicotyledonous plants that inhabit aquatic and wetland places, places permanently or seasonally wet. It is not intended to be a study of ecology of hydrophytes. It is hoped that, as a taxonomic-floristic work, it will have value to ecologists, to governmental agencies concerned with environmental problems , to contractual firms engaged in environmental impact analyses, to individuals with general ecological interests, and to students in colleges and universities. Recognizing that these prospective users will have had diverse or limited experience in plant identification, we have sought to use, whenever possible, nontechnical language. We trust that we may have achieved this goal to a limited but useful extent. A glossary is included to help with the technical terminology necessary to describe features for reasonable understanding. Those states of the southeastern United States for which this manual affords botanical coverage (see preface) encompass parts of the following physiographic provinces: Atlantic and Gulf coastal plains, southern Appalachian highlands, flanked on the east by the Piedmont plateau, and on the west by the Appalachian plateau, the interior lowlands, and the interior highlands. The region has a diverse topography, a wide range of habitat types, varied and variable organismal communities, thus diverse ecosystems. In many instances our ecosystems , complex and not readily delimited to begin with, are becoming increasingly blurred and degraded both by man's overt direct manipulation and by the vicissitudinous alterations attendant upon one or another of his activities. FORMAT The text for each species includes a statement indicating the habitat or habitats in which the plant usually grows and a statement of its geographic distribution. Most of the statements must be taken as generalities, subject in many instances to exception and incompleteness. For the stated geographic ranges, especially for widely distributed species, we relied upon relatively recent taxonomic revisions whenever possible. Otherwise, we followed or adapted from ranges given in floras and manuals, particularly Small (1933), Fernald (1950), Gleason (1952), and Correll and Correll (1972). The range for each of the wide-ranging species is expressed as nearly as feasible according to the geographic areas which mark the limits of range. In most cases the northern boundary is given first, beginning at the northeast, in the style of the widely used floras by Fernald and Gleason. The reference list following the glossary includes, for the most part, general references and appropriate papers from the series prepared for a biologically oriented generic flora of the southeastern United States, the latter a joint project of the Arnold Arboretum and the Gray Herbarium of Harvard University, chiefly under the direction of Carroll E. Wood, Jr. and Reed C. Rollins. Numerous literature citations are placed in the text with the treatment to which they most specifically apply. DISTRIBUTION OF AQUATIC AND WETLAND PLANTS The subject of this work, aquatic and wetland plants, would seem to carry with it the assumption that some definitive physical boundaries exist so that one can attribute a given plant's occurrence to an aquatic habitat or to a wetland habitat. This is true, however, only to a very limited extent, for the physical boundaries are generally not precise, neither are the habitat requirements or tolerances of a great many species. Some sites, which have waterlogged soils during times of high precipitation, may dry out completely during intervening drought periods. Aquatic and wetland plants commonly are present sporadically in their habitats. Plants of 1 Introduction The aim of this work is to aid in identifying native and naturalized dicotyledonous plants that inhabit aquatic and wetland places, places permanently or seasonally wet. It is not intended to be a study of ecology of hydrophytes. It is hoped that, as a taxonomic-floristic work, it will have value to ecologists, to governmental agencies concerned with environmental problems , to contractual firms engaged in environmental impact analyses, to individuals with general ecological interests, and to students in colleges and universities. Recognizing that these prospective users will have had diverse or limited experience in plant identification, we have sought to use, whenever possible, nontechnical language. We trust that we may have achieved this goal to a limited but useful extent. A glossary is included to help with the technical terminology necessary to describe features for reasonable understanding. Those states of the southeastern United States for which this manual affords botanical coverage (see preface) encompass parts of the following physiographic provinces: Atlantic and Gulfcoastal plains, southern Appalachian highlands, flanked on the east by...