Stomatal classifications — a review

Summary In order to avoid confusion terminologies to describe: (i) adult stomatal types; (ii) stomatal ontogeny; (iii) stomatal structure; and (iv) stomatal distribution should be used separately. (i) Thirteen adult stomatal types — anomocytic, anisocytic, actinocytic, diacytic, paracytic, cyclocytic, polocytic, desmocytic, pericytic, tetracytic, hexacytic, hemiparacytic, and staurocytic; (ii) three ontogenetic groups — perigenous, mesogenous and mesoperigenous; (iii) five for stomatal structure — acyclic, bicyclic or diacyclic, tricyclic, tetracyclic and polycyclic and (iv) three for stomatal distribution — epistomatic, hypostomatic and amphistomatic widely used in literature should be accepted. Stomatal meristemoid or stoma mother cell should be replaced by a term “stomatocyte”.