Some plants found in the wild or developed in cultivation descend from two different species, usually closely related, that have crossed. These plants are called “hybrids”. In many cases, the parent species are known, yet in others they are somewhat ambiguous. The TDC shows the parent species in the following format:
Elymus × dorei [hystrix × trachycaulus]
which indicates that the hybrid, Elymus × dorei, is a cross between the two species, Elymus hystrix and Elymus trachycaulus.
The International Code of Botanical Nomenclature specifies that hybrid names begin with, or include, a multiplication sign, “×”.
Hybrids are especially common in the Poaceae (Grass Family), Cyperaceae (Sedge Family), and the Orchidaceae (Orchid Family).