II. PERICARP ANATOMICAL STUDY OF SOME LAMIACEAE NUTLETS IN SAUDI ARABIA AND ITS TAXONOMIC SIGNIFICANCE

Abstract

The nutlets transverse sections of 23 selected taxa belonging to 12 genera of Saudi Arabia Lamiaceae were examined using light microscope and detailed description of the pericarp anatomical characteristics were provided. Nutlets have shown obvious differences in the presence or absence of hairs, papillae, mucilage, endosperm and crystals, also, in thickness of pericarp layers, parenchymatous and sclerenchymataus layers. The relationships between the studied taxa were presented as phenogram. This study confirms the usefulness of the nutlet anatomical features as additional characters in taxonomical studies of the Lamiaceae especially mucilage production (myxocarpy) and the sclerenchymatous layer (shape, pigment, and cavity) of the endocarp. They are diagnostic at the generic and subfamily levels. The anatomical studies indicate the family is polymorphic in pericarp characters.