Histo-anatomical observations on some Orchis species (Orchidaceae) from the Eastern Mediterranean

Anatomical and histological observations were carried on leaves and stems of some Orchis species collected in the Greek Islands of Rhodes and Crete. Leaves of all species examined showed common morphological aspects which appared coherently related to mediterranean environment, where these plants grow, and to their adaptive strategy. some morphological characteristics always occurred in all Orchis stems: a sclerenchymatous sheath was observed in the outer part of cortex; the inner part of ground tissue, the pith, consisted of thin-walled cells; vascular bundles, embedded in parenchyma, were nearly arranged in a circle on the periphery of the ground tissue.