The Iranian enigmatic endemic Salvia majdae (Lamiaceae): its taxonomic status based on floral ontogeny

Abstract

Since the first description of Salvia majdae (syn. Zhumeria majdae) in 1967, its taxonomic status has remained an enigma within Salvia senso lato due to its unusual characters, in particular the floral structure. Based on recent molecular phylogenetic data, two defensible opinions on its status have been proposed. Here, we studied the floral development of this species using scanning electron microscopy to resolve this ambiguity. The aspects of floral symmetry were also studied. Like species of Salvia and representative genera of Lamiaceae, the initiation sequence of sepals and stamens in S. majdae is unidirectional from adaxial to abaxial and reverse, respectively. The flowers show temporal overlaps in initiation of petals and stamens. However, in contrast, the bidirectional initiation of the petals in S. majdae is reversed, starting with the abaxial middle petal, followed by the two adaxial ones, and then finally ending with the two lateral ones. The filaments of the sterile stamens are elongated and exposed as staminodes thorough development. We conclude that subequal growth of the calyx lips, weak cochlear aestivation and bidirectional initiation of the petals and well‐developed sterile stamen primordia are responsible for the weak floral asymmetry in S. majdae. Based on these data, S. majdae shows significant differences from Salvia.