Taxonomic relevance of leaf epidermis in the African irvingia hook. f. (Irvingiaceae)

Abstract

A comparative study of the leaf epidermis characters of three African species of Irvingia was undertaken using light microscopy with a view to provide additional taxonomic anatomical characters for distinguishing the species. Until now, the distinction of the species was based on weak data from exomorphology, biochemistry and organoleptic features with their attendant taxonomic inadequacies.
Majority of the variations were found in stomata number, cell number on adaxial surface and stomatal index of I. gabonensis, I. smithii and I. wombolu respectively, and they appear useful in differentiating the species but interstomatal epidermal cell number, paracytic stomatal type and hypostomata are generic constant. Amphibrachyparacytic stomata type, styloids and peltate scales are useful for
distinguishing I. smithii from other species, while undulate epidermal cell shape and lack of crystals on the adaxial surface of the epidermis separate I. wombolu from I. gabonensis. New stomatal types are recorded for the genus. An artificial bracketed identification key is presented for delimiting the species.