Glandular Hair Formation in Origanum Species

Abstract

Eleven Origanum species were investigated in this study. In all these species, leaf glandular hairs have the same structure and they have been found to follow a common developmental pattern. They originate from a single protodermal cell which divides successively parallel to leaf surface to give rise to the foot cell, the stalk cell and the mother cell of the head. The latter undergoes a series of symmetric and asymmetric anticlinal divisions resulting in a 12-celled head (four small cells in the centre and eight large cells peripherally arranged). Determination of the glandular scale morphology within the Lamiaceae genera and further comparison between the various gland types would be helpful to systematics.