Anatomical and histochemical characterization of Syzygium travancoricum Gamble (Myrtaceae)

Syzygium travancoricum Gamble popularly known as "Kulavettimaram" or "Kulirmaavu" is a least explored endemic endangered taxa of Southern Western Ghats, Kerala. The species is often misidentified due to its close resemblance with allied species and no other studies have been reported on the anatomical and histochemical characters of this species. This article aims to evaluate the anatomical and histochemical characteristics of various vegetative parts of S. travancoricum. Anatomical and histochemical characters of bark, stem, and leaf were analyzed using standard microscopic and histochemical procedures. S. travancoricum possessed distinct anatomical characters such as, paracytic stomata, arc shaped midrib vasculature, continuous sclerenchymatous sheath around the midrib vascular region, single layer of adaxial palisade layer, presence of druses, and quadrangular cross section contour of stem which could be combined with additional morphological and phytochemical characteristics, relevant for species identification. The bark showed the presence of lignified cells, isolated groups of fibers and sclereids, starch depositions and druses. Stem has quadrangular outline with well-defined periderm. The petiole and the leaf blade have abundance of oil glands and druses with paracytic stomata. The anatomical and histochemical characterization are potential tools for the delineation of confusing taxa and provide substantial evidence to their quality control.