Since binomials are required to be unique only within a kingdom, two species can share the same binomial name if they are in different kingdoms. I know of one instance of this, Orestias elegans: this name denotes a species of fish (kingdom Animalia) as well as a species of orchid (kingdom Plantae).

Are there other instances where one binomial name validly refers to two (or more!) species?

  • $\begingroup$ This is a fascinating and surprising tidbit of information that practically begs to be used as the point of a puzzle story. $\endgroup$ Nov 12, 2018 at 10:59
  • $\begingroup$ But why on earth did anyone think it would be a good idea to allow such a thing? $\endgroup$
    – user21820
    Nov 12, 2018 at 16:10

3 Answers 3


There are four other instances of species-level hemihomonyms I can find:

  1. Agathis montana can be either a critically endangered species of conifer or a parasitic insect.
  2. Centropogon australis can be either a fish or a plant with a long red flower.
  3. Asterina gibbosa can be either a sea star or a type of fungus
  4. Baileya australis can be a moth or a yellow flowering plant

In addition to the five listed above, Wikipedia currently shows two others, for a total of seven:

Ficus variegata can be either a sea snail or a fig

Tritonia pallida can be either a nudibranch or an iris

See "Hemihomonyms" here.


Two others for posterity, since I haven't seen others bring it up. Rhaphidophora is a genus of flowering plants AND of cave crickets, and there are two species-level hemihomonyms. R. beccarii is an uncommon houseplant and its relative R. neglecta is much rarer, but both are still documented. There's hardly any record that the cave crickets with these names exist, but they both seem to be accepted species with type specimens and all. I looked hard for images of either one and came up empty handed.

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    $\begingroup$ Very nice first post, welcome to Biology. Please take our tour and refer to the help center for guidance as and when, enjoy the site. $\endgroup$ Nov 26, 2021 at 13:43

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