In lieu of an abstract, here is a brief excerpt of the content:

Introduction The aim of this work is to aid in the identification of vascular plants which are native or have become naturalized in aquatic and wetland habitats of the Northeast. As a taxonomic-floristic work, it is designed to be of value to biologists, students of biology, conservationists, environmental consultants, personnel of local, state, and federal agencies, and any individuals with general ecological interests . Recognizing that the prospective users will vary with respect to experience in plant identification, we have attempted to utilize less technical language wherever possible . Glossaries are included to clarify terminology. Illustrations are also provided to aid the users; the 606 plates include figures of 1087 taxa, with 92 percent of the taxa fully or partly illustrated. To facilitate the identification process further, references to the figures are included in the keys. The geographical range covered by this work includes the region from Newfoundland west along the 50th parallel to southeastern Manitoba and Minnesota, south to Virginia and Missouri. Thus, on the southern edge, our range abuts the range covered by Drs. Godfrey and Wooten in their Aquatic and Wetland Plants ofthe Southeastern United States. In order to increase the usefulness of our manual we have expanded our coverage to include plants of wetland habitats as well as truly aquatic habitats. Although we have included plants of bogs and salt marsh habitats, we have not included terrestrial plants which may occur typically on flood plains, in woodland springs, or along vernal woodland or seasonal alpine brooks. Admittedly it is sometimes difficult to determine the outer boundary of a wetland habitat, therefore the decision to include or exclude certain species has been necessarily somewhat subjective . Our tendency has been toward inclusion rather than exclusion. Some plants which are only occasionally found in the water may be mentioned in the text but omitted from the keys. The keys in the manual treat a total of 1139 species (1186 taxa) representing 295 genera in 109 families of vascular plants. The families presented follow the classification system of Tryon and Tryon (1982) for Pteridophytes , the classification of Cronquist, Takhtajan, and Zimmermann (1966) for Gymnosperms, and the system of Cronquist (1981) for Angiosperms. As in Cronquist's system, the families ofthe Dicotyledons (class Magnoliopsida ) which constitute Volume 1 precede those of the Monocotyledons (class Liliopsida) in Volume 2. Families are then arranged by subclasses within the 2 classes. Genera xi and species are then arranged in the order in which they key out. Infraspecific taxa considered important from an aquatic standpoint have been included in the keys. Because of the considerable variation in vegetative morphology exhibited by many aquatic plants, formal recognition of the rank forma has not been applied here. All too often a single plant can change from one morphological form to another as the season progresses and water levels change in aquatic and wetland habitats. This morphological variability has, however, been taken into account in constructing the keys; thus some species may key out in more than one place. The generic descriptions are intended to be diagnostic, providing additional information which may not be utilized in the construction of the keys but which may be useful in the identification process. We have tried to include as many illustrations as possible to aid also in the process of identifying specimens, and have especially attempted to provide figures that show the important features . Because of spatial constraints we have elected to include only selected family deSCriptions, because they are readily available in numerous works. We have attempted to utilize vegetative features as much as possible to facilitate the identification of plants in vegetative condition, however, it must be recognized that for many species a reliable determination ofthe identity of a plant will require flowering and/or fruiting material . This is especially true of some families, such as the Cyperaceae, Orchidaceae, Poaceae, and Sparganiaceae. In general, it is much more difficult to identify aquatic and wetland plants early in the growing season. Ideally, in inventory work one should be able to make observations and collect specimens over the entire growing season . Thus, one can observe the relationship of growth forms in aquatics such as Sclerolepis uniflora whereby the plants remain vegetative in the submersed aquatic form, but as the water level drops, the stems of the aquatic form stranded along the newly exposed shore give rise to upright , seemingly unrelated fertile shoots. While the aquatic form of this species will key out in Key 3 of the General Keys, keying out the...

Share