The International Nepenthes Grex Registry

Grex Naming Formulas

The following text describes the grex naming practices employed in the INGR. Part A gives the standard formula for naming new hybrid greges, hybrid grex remakes, and remakes of historical hybrids. Part B gives the standard formula for naming horticulturally bred species. The Definitions page gives additional explanatory information for each part of a standard grex name.
  1. New greges and remakes of registered greges and historical hybrids.

    GENERIC - Grex1/Historical Epithet - Grex2 - (A x B) - Date - Breeder

    The GENERIC name is mandatory but may be shortened to 'N.' (Nepenthes Generic name: Latin, italic, first letter capitalized).

    The Grex1 epithet is mandatory. A grex epithet must follow the Definitions but are chosen at the discretion of the breeder. Grex epithets are fixed and are retained in all future crossings of the same genetically identical, individual plants ("clones"), whether those individuals be species, members of a registered grex, historical hybrids, or natural hybrids. Because individual plants are either male or female (Nepenthes as a rule are monoecious), grex registrations are sex-respective by default.

    If the grex is a remake of a historical hybrid, then the historical epithet (e.g., x rokko) serves in place of the Grex1 epithet.

    The Grex2 is mandatory if either of the following two conditions apply:

    1. The grex to be registered is a remake of an existing registered grex.
    2. A Historical Epithet is quoted in the Grex1.


    • N. Predator (N. truncata x hamata) 2008-5-26 Exotica Plants
    • N. Dangnoi (N. mirabilis var. globosa x ampullaria 'Cantley's Red') 2009-10-17 Suwarun Suphawut

    • When different breeders utilize genetically identical parent plants to (re)create a grex:
    • N. Blackbird (N. inermis x ramispina) 2006-11 Browning Nursery
    • N. Blackbird Pinole (N. inermis x ramispina) 2008-3 Pinole Gardens

    • When different breeders utilize genetically different plants:
    • N. Blackbird (N. inermis x ramispina) 2006-11 Browning Nursery
    • N. Bluejay (N. inermis x ramispina) 2008-3 Pinole Gardens

    • A remake of a historical hybrid:
    • N. x rokko Pinole (N. "thorelii" x maxima) 2008-5 Pinole Gardens

    The (A x B) is a shorthand notation for a record of derivation. For the purposes of registry, the genetic derivation of a plant is to be expressed in a formula recording the female plant first and the male plant second, i.e., (N. maxima x ventricosa), in which maxima is the female parent and ventricosa is the male. Complex crosses having more than two species as ancestors are to be described in the same fashion, employing set theory type bracketing to clearly define the order of crosses involved, and factored to the species level1.


    • (N. x rokko x x dyeriana) x ventricosa

    • must be factored to:

    • ((N. "thorelii" x maxima) x ((N. northiana x maxima) x (N. rafflesiana x veitchii))) x N. ventricosa

    The (A x B) expression of derivation is mandatory and non-commutative with the female plant always listed first in the expression.

    The Date is the date of pollination.

    The Breeder is the nursery or individual who bred the plant.

    1 Historical epithets and grex names are not allowed in the expression of derivation, which must instead be factored to species level.

  2. Horticulturally Bred Species

    GENERIC - Natural Epithet - Grex1 Grex2 - (A x B) - Date - Breeder

    The Natural Epithet is mandatory and precedes the mandatory Grex epithets. The Natural Epithet is the existing species name. The default sources for Natural Epithets are the ICPS database and Wikipedia species list.