In September 1786, well-known German writer and naturalist – and originator of the term ‘morphology’ – Johann Wolfgang von Goethe looked out of a carriage passing through the foothills south of Munich and observed changes in the leaves of some local vegetation, including, as he noted, willows and gentians. He speculated that these changes might be related to changing environmental conditions related to altitude. A rough sketch of the differing morphology of a willow accompanies his notes.
In a new article published in Annals of Botany, Ulrich E. Stegmann asks whether Goethe’s drawing represents the first illustration of environmentally induced intraspecific trait variation (ITV) in the wild. Goethe’s notes describe the twigs as being “stronger and more sappy, the buds stood closer together, and the leaves broader” in the lower regions, while at greater altitudes, “the stalks and branches became more fragile, the buds were at greater intervals, and the leaves thinner and more lanceolate.”
Goethe may have been mistaken in his assessment, the variation due to misidentification, phenotypic plasticity, or genetic differences, but the sketch would seem to be the first incidence of this phenomenon being illustrated. The concept of morphological differences caused by the environment goes all the way back to the 4th century BC, when the Greek naturalist Theophrastus, known as the Father of Botany, noted that trees were “taller and finer in appearance” at lower altitudes. “The dwarfing of plants at higher altitudes became a prime example of environmentally-mediated ITV during the early and mid-19th century. It was mentioned by naturalists such as Lamarck, Humboldt & Bonpland, and Darwin. Yet only in the 1890s did ITV emerge as an object of sustained empirical inquiry,” writes Stegmann.