Leaf structure

This monograph examines the leaf structure of plants in various montane habitats, focusing on the relationship between leaf structure and environmental stresses such as isolation, frost, and drought. It draws on original observations from mountainous regions in Venezuela and Argentina, involving the author, her students, and colleagues. The plants studied employ diverse strategies to adapt to their environments, showcasing a range of structural traits like reduced surface/volume ratios, rolled leaves, crypts, water-storing tissues, and thick, cutinized upper epidermis cells. Tannic substances provide UV protection, while colorless parenchyma may result from chlorophyll decomposition due to excessive isolation. Many species exhibit leathery leaf consistency, attributed to various anatomical structures, with Senecio rex displaying particularly thick palisade cell walls. Most species have sun leaves, and leaf consistency correlates with leaf fall. The most xeromorphic adaptations are observed in Espeletia at elevations of 2000 to 4000 m a.s.l. The study also addresses physiological and ecophysiological aspects. Notably, several Andean species, including Krameria lappacea, have significant medicinal uses, with the latter nearly extinct due to its tannin content. The medical applications of paramo plants like Espeletia and Carramboa are also highlighted.