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Grex (horticulture)

    The term grex (pl. greges), derived from the Latin noun grex, gregis meaning flock, has been coined to expand the Linnean binomial system to include hortucultural hybrids. Gregaric names are widely used in particular for orchids. A grex may be:
    • a species (usually called a species, instead of a grex)
    • a hybrid between two greges.

    Linnean Treatment of Natural Hybrids: the Nothospecies

    Naturally occurring interspecific hybrids are given Linnean binomials with the letter "x" between the generic epithet and the nothospecific epithet. An offspring of the nothospecies, either with the nothospecies or either of the parental species as the other parent, has the same nothospecific name. That is, the nothospecific binomial is an alias for a list of the ancestral species.

    For example, a naturally produced hybrid between Cattleya warscewicziiRchb.f. 1854 and Cattleya aurea Linden 1883 would be called Cattleya Xhardyana Sander 1883 or Cattleya x hardyana. An offspring of a Cattleya x hardyana pollenized by another Cattleya x hardyana would also be called Cattleya x hardyana. Cattleya x hardyana would also be the name of an offspring of a Cattleya x hardyana pollenized by either a Cattleya warscewiczii or a Cattleya aurea, or an offspring of either a Cattleya warscewiczii or a Cattleya aurea pollenized by a Cattleya X hardyana

    Hortucultural Treatment of Greges

    A non-specific grex is initially produced by the deliberate hybridization of two different greges, and is treated as if it were some new species. Any additional plants produced from the hybridization of the same two parental greges belong to the new grex, as do any offspring of that same grex. The non-specific gregaric name differes from a specific name in that the gregaric part of the name is capitalized, is not italicized, and may consist of up to four words.

    For example: an artificially produced hybrid between Cattleya warscewiczii and Cattleya dowiana (or Cattleya aurea, which the RHS, the international orchid hybrid registration authority, considers to be a mere variety of and therefore synonymous with C. dowinana) is called Cattleya Hardyana. An artificially produced seedling that results from pollenizing a Cattleya Hardyana with a Cattleya Hardyana is also a Cattleya Hardyana. However, the hybrid produced between Cattleya Hardyana and Cattleya dowiana is not Cattleya Hardyana, but Cattleya Prince John. Similarly, the artifical hybrid produced between Cattleya Hardyana and Cattleya warscewiczii is Cattleya Eleanor. These relationships are often described in the following manner:
    C. Hardyana = C. warscewiczii x C. dowiana
    C. Eleanor = C. Hardyana x C. warscewiczii
    C. Prince John = C. dowiana x C. Hardyana

    Due to the maintenance of many interspecific (and even intergeneric) barriers in the Orchidaceae 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.
    Image:Cattleya warscewiczii.jpg|Cattleya warscewicziiImage:Cattleya dowiana 1880.jpg|Cattleya dowiana
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