Are Petrea volubilis and P. arborea (Verbenaceae) Conspecific? New Insights From Anatomy

ABSTRACT Correct taxonomic identity is crucial in plant taxonomy, especially in the case of practically good species that are considered conspecific due to lack of sufficient reliable data, such as those studied here. Linnaeus in 1753 established the genus Petrea L. with a single species P. volubilis L. Later, Kunth added two species P. arborea Kunth and P. rugosa Kunth. Though, Moldenke in his monographic work considered both P. arborea and P. volubilis as good species, however, recent works treated both conspecific and accept P. arborea as synonym of P. volubilis . In the present study, comprehensive morphological, micro‐morphological and anatomical investigations were conducted on the mentioned two species of Petrea , viz., P. arborea and P. volubilis , collected from different regions of India. Detail morphological (habit and leaf), micro‐morphological (both light microscopy and scanning electron microscopy (trichomes and stomata)) and anatomical (t.s. of internode, leaf midrib and minor venation) characteristics were monitored. The studied results advocate that a few significant morphological, micro‐morphological and anatomical traits are critical in both the species and have immense diagnostic value, which denotes them as good species rather than conspecific.