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 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:
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.