Grex (horticulture)

They can optionally be given Linnean binomials with a multiplication sign "×" before the species epithet[4] for example Crataegus × media.

The nothospecific binomial is an alias for a list of the ancestral species, whether the ancestry is precisely known or not.

Since the 1982 meeting of the International Botanical Congress, such subordinate taxa are considered varieties (nothovars).

Because many interspecific (and even intergeneric) barriers to hybridization in the Orchidaceae are maintained in nature only by pollinator behavior, it is easy to produce complex interspecific and even intergeneric hybrid orchid seeds: all it takes is a human motivated to use a toothpick, and proper care of the mother plant as it develops a seed pod.

When a hybrid cross is made, all of the seedlings grown from the resulting seed pod are considered to be in the same grex.

The rules for the naming of greges are defined by the International Code of Nomenclature for Cultivated Plants (ICNCP).

[13] New grex names are now established by the Royal Horticultural Society, which receives applications from orchid hybridizers.