Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animal life is fauna. Flora, fauna and other forms of life such as fungi are collectively referred to as biota. Sometimes bacteria and fungi are also referred to as flora, as in the terms gut flora or skin flora.
The word "flora" comes from the Latin name of Flora, the goddess of plants, flowers, and fertility in Roman mythology.
The distinction between vegetation (the general appearance of a community) and flora (the taxonomic composition of a community) was first made by Jules Thurmann (1849). Prior to this, the two terms were used indiscriminately.
Plants are grouped into floras based on region (floristic regions), period, special environment, or climate. Regions can be geographically 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.
The flora of a particular area or time period can be documented in a publication also known as a "flora" (often capitalized as "Flora" to distinguish the two meanings when they might be confused). Floras may require specialist botanical knowledge to use with any effectiveness. Traditionally they are books, but some are now published on CD-ROM or websites.
It is said that the Flora Sinensis by the Polish Jesuit Michał Boym was the first book that used the name "Flora" in this meaning, a book covering the plant world of a region. However, despite its title it covered not only plants, but also some animals of the region.
A published flora often contains diagnostic keys. Often these are dichotomous keys, which require the user to repeatedly examine a plant, and decide which one of two alternatives given best applies to the plant.
Wikipedia has the following mainly flora categories:Flora by continent
Flora by country
Flora by region