Comparative Anatomy of the Aerial Roots of Blue and Red Vandas and its Diagnostic Significance

The two highly endangered orchid species, Vanda coerulea Griff, ex Lindl. (Blue Vanda) and Renanthera imschootiana Rolfe (Red Vanda), could be easily identified when those are in flowering states. However, it is difficult to identify them in their vegetative conditions since both of the species resemble one another in apparent morphology. In the present study, efforts have been made to identify them in their vegetative conditions by the anatomical structures of aerial ischolar_mains studied under SEM (Scanning Electron Microscope) as well as Light Microscope. The presence of medullary bundles in Red Vanda seems to be a unique diagnostic feature, which could be used to identify the said plant species in its vegetative condition.