Plectenchyma - types and definitions

Abstract

The different layers of stratified thallus of most lichens are formed from variations in the patterns of groups of hyphae that can be organized into tissue with the appearance of parenchymatous organization. This tissue type is known as plectenchyma (or pseudoparenchymatous tissue) but in lichenized fungi the terminology applied to subtypes of plectenchyma has not been standardized and varies from author to author. The differences between the definitions of the authors lead to conceptual problems that interfere directly in the clear and technical description of the different anatomical layers that exist in lichens. With the improvement of observation systems, through the use of light microscopy and transmission electron microscopy and scanning, the micro morphological observations have shown great potential for application in many taxonomic groups of lichens showing the importance of standardization of terms used in anatomical studies.