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Grex (horticulture)

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**1. Botanical Nomenclature and Naming Rules:**
– Grexes exist within the framework of the botanical nomenclature of hybrid plants.
– Interspecific hybrids are treated as nothospecies under the International Code of Nomenclature for algae, fungi, and plants.
– Offspring of a nothospecies have the same nothospecific name.
– Subordinate taxa to nothospecies are considered varieties (nothovars) since 1982.
– Hybrid names can include Linnean binomials with a multiplication sign.
– Grex names follow rules defined by the International Code of Nomenclature for Cultivated Plants.
– Grex names are in a living language, not Latin.
Cultivar names distinguish individual plants within a grex.
– The first established grex name requires a description specifying two parents.
– New grex names are established by the Royal Horticultural Society.

**2. Horticultural Treatment and Registration:**
Orchid hybrid seeds can be easily produced with human intervention.
– All seedlings from a hybrid cross belong to the same grex.
– Reciprocal crosses are part of the same grex.
– Offspring of the same grex share the grex name as their parents.
Cultivar names are given to superior plants within a grex.
– A description specifying two parents is required to establish a grex name.
– Grex names apply to all hybrids between the specified parents.
– Exceptions are permitted if one parent is known only to genus level.
– Grex names are used only within the orchid family.

**3. Relationship and Comparison with Nothospecies:**
– Greges and nothospecies are similar concepts but have differences.
– Nothospecies are used for all plants, while greges are specific to orchids.
– Greges and nothospecies can have the same parentage but differ in scope.
– Hybrids between a grex and a species/nothospecies are named as greges.
– Back-crosses are named using the nothospecies parent’s name.

**4. Grex, Group, and Cultivar Naming Conventions:**
– Grex denotes a group of hybrid plants that share the same parentage.
– Grex names consist of a grex epithet followed by the names of the parents in brackets.
– Grex names are written in single quotes and are not italicized.
– Group names are used to denote a set of cultivars within a species.
– Group names are written with an initial capital letter, enclosed in single quotes, and not italicized.
Cultivar names are used to denote cultivated varieties of plants.
Cultivar names are written in a specific format according to ICNCP guidelines, with an initial capital letter, italicized, enclosed in single quotes.

**5. ICNCP Rules and Guidelines:**
– The International Code of Nomenclature for Cultivated Plants (ICNCP) provides rules for naming plants in cultivation.
– ICNCP rules cover various aspects such as grex, group, and cultivar names.
– ICNCP guidelines ensure consistency and accuracy in naming cultivated plants.
– Adherence to ICNCP rules is essential for standardization in horticultural nomenclature.
– ICNCP rules are periodically updated to reflect advancements in horticulture.

The term grex (plural greges or grexes; abbreviation gx), derived from the Latin noun grex, gregis, meaning 'flock', has been expanded in botanical nomenclature to describe hybrids of orchids, based solely on their parentage. Grex names are one of the three categories of plant names governed by the International Code of Nomenclature for Cultivated Plants; within a grex the cultivar group category can be used to refer to plants by their shared characteristics (rather than by their parentage), and individual orchid plants can be selected (and propagated) and named as cultivars.

× Lycamerlycaste Hera gx is a grex of orchid hybrids in the nothogenus × Lycamerlycaste J.M.H.Shaw. It consists of hybrids between members of a grex (× Lycamerlycaste Brugensis gx) and a species (Lycaste cruenta Lindl.).
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