Biochemistry in the Taxonomy of Lichens

Abstract

THE application of biochemical methods to plant taxonomy was first made in the lichens, in 1867, when potassium hydroxide and calcium hypochlorite were found to give characteristic colour reactions when applied to the thallus of certain species. Most present-day lichenologists employ these reactions as an important character in the description of species. In a large number of lichen species the exact constitution of the lichen acids causing colour reactions is known, mainly owing to the researches of Zopf¹ and Asahina^2,3. The latter has originated a method of microchemical analysis whereby the lichen acids can be determined by the form of the crystals which they produce under the microscope when recrystallized from various, solutions⁴, this method requiring the extraction of only a small portion of the thallus with acetone.