Some of the biological problems presented by bracken, Pteridium aquilinum (L.) Kuhn, are
posed. Its taxonomic position within the Pteridophyta and the delimitation of entities within …

An historical summary of the distribution and abundance of submerged aquatic vegetation
(SAV) in the Chesapeake Bay is presented. Evidence suggests that SAV has generally been …

The geographic distribution of C4 species in the Dicotyledonae of North America was
examined in relation to climatic parameters in an attempt to identify environmental …

Lythrum salicaria L.(purple loosestrife, spiked loosestrife, long purples, o sally) of the
Lythraceae is a tall, perennial, purplish-red-flowered herbaceous p wetland habitats. As …

The taxonomy of Salix in the southeastern United States was studied in the field and
herbarium. Twelve species and one variety of native willows are recognized and seven …

Although seed dispersal is assumed to be a major factor determining plant community
development in restored wetlands, little research exists on density and species richness of …

Tidal freshwater marshes have diverse plant communities that vary spatially and temporally
due to hydrology, animal activity, and other factors. Development of urban centers along …

A 1978–81 survey of submersed aquatic macrophytes in the tidal Potomac River showed
that there were virtually no plants in the freshwater tidal river between Chain Bridge and …

Rorippa consists of those yellow-petaled, numerous-seeded, readily-dehiscent-fruited
marsh and shore plants in the Cruciferae. Distributed primarily in temperate, less so in …

Results of a 3-year survey (1978–1980) and review of historic trends have shown a major
decline in the number of species and the distribution of submersed aquatic macrophytes in …