This category is primarily for articles whose title (and subject) is a common name for a plant that does not correspond to a single scientifically recognized species (or other taxonomic rank). There should generally be some shared characteristic that can be discussed in an article (e.g. cardamom is a spice derived from multiple species; tree fern describes large ferns with a tree-like trunk).
In addition, there are subcategories for redirects from common names to scientific names, and for set index articles (simple lists of different plants known by the same common name).
For disambiguation pages covering a term used as a common name used for several plants see Category:Plant common name disambiguation pages. The contents of Category:Redirects from scientific names of plants are redirects from the currently accepted scientific name of a plant to an article titled by a common name.