This document serves as a standardized, comprehensive inventory designed to identify and classify plant species based on their frequency of occurrence in wetland habitats. Porter B. Reed, acting under the auspices of the U.S. Fish and Wildlife Service, compiled this data to provide a consistent scientific framework for environmental scientists, regulators, and land managers. The work establishes a systematic indicator status for various flora, facilitating the accurate delineation of wetland boundaries across different geographic regions.

Experts and environmental professionals recognize this list as a foundational reference for regulatory compliance and ecological assessment. Readers frequently note the technical nature of the data, which is intended for use by trained specialists rather than the general public.