Epidermal features allowing identification of evolutionary lineages in the Ocotea complex (Lauraceae)

Epidermal characters are widely used in identification of fossil plant material, yet they are insufficiently known in many extant taxa. Here, we examined the cuticle and stomatal complex in 85 species of the Ocotea complex by optical and scanning electron microscopy. We defined 19 types of stomatal surface appearance, which were mostly consistent with genera or species groups recognized based on reproductive characteristics. The epidermal features support the conclusion derived from DNA analyses that Ocotea is heterogeneous in its current circumscription. We suggest an evolution of the subsidiary cells in the Ocotea complex species from asymmetric to symmetric, and from relatively wide to narrower shapes of the stomatal complex.