UNUSUAL FEATURE OF STOMATAL MICROANATOMY IN CERTAIN TAXONOMICALLY-RELATED EUCALYPTUS SPP

The line of closure in the stoma in fully grown adult leaves of certain eucalypts is formed by special ridges of cuticle called 'stomatal bars' developed at the line of closure itself or from upgrowth of the cuticle of the lower surface of the guard cells. Stomatal bars, previously discovered in three members of the informal group 'Bisectae' are shown to be restricted to certain species in that group. Possession of stomatal bars may affect stomatal performance but does not appear to be a general adaptive response to the habitats of the species which possess them. More probably, the possession of stomatal bars is an inherited character with taxonomic value. The presence of stomatal bars in other genera is discussed. © 1979, Annals of Botany Company.