Plants are grouped into floras based on region (
floristic regions), period, special environment, or climate. Regions can be distinct
habitats like mountain vs. flatland. Floras can mean plant life of a historic era as in
fossil flora. Lastly, floras may be subdivided by special environments: •
Native flora. The native and indigenous flora of an area. •
Agricultural and horticultural flora (garden flora). The plants that are deliberately grown by humans. •
Weed flora. Traditionally this classification was applied to plants regarded as undesirable and studied in efforts to control or eradicate them. Today the designation is less often used as a classification of plant life since it includes three different types of plants:
weedy species,
invasive species (that may or may not be weedy), and native and introduced non-weedy species that are agriculturally undesirable. Many native plants previously considered weeds have been shown to be beneficial or even necessary to various
ecosystems. ==Documentation==