August Grisebach and Floral Provinces

In 1872 August Grisebach (1814–79), professor of botany at the University of Gottingen, Germany, published a two-volume work that greatly advanced the study of phytogeography. Its full title was Die Vegetation der Erde nach ihrer klimatischen Anordnung: Ein Abriss der vergleichenden Geographie der Pflanzen (The vegetation of the Earth according to its climatic distribution: A sketch of the comparative geography of plants). Grisebach was one of a number of geographers who had been inspired by the travels of Alexander von Humboldt. In 1839 and 1840 Grisebach traveled through the Balkans in southeastern Europe and Turkey studying the geography and the plants. His account of these and other travels established his scientific reputation. He devised the term Geobotanik (geobotany) to describe his work.

Humboldt had drawn isotherms—lines joining points on the Earth's surface or at the same elevation with respect to the surface, where the temperature is the same—across maps of the world. These defined the boundaries of climatic—and therefore vegetational—zones. For Humboldt's followers, including Grisebach, this offered a new approach to the study of plant distribution. Rather than listing the plants of a region and then trying to figure how they came to be there, the Humboldtian alternative was to examine the ways in which plants were adapted to the climatic conditions in which they lived. This led Grisebach to the realization that communities occurring in a particular climate were similar, even though the species composing them were different. North American prairie, for instance, was very similar to European steppe and the South American pampas, but each type of grassland supported its own species of grasses and herbs. In the same way, humid tropical forests were similar whether they occurred in South America, Africa, or southern Asia, although each had its own suite of tree species. Grisebach called an assemblage of plants determined by climate a formation. This was a new way of looking at plants. They could now be studied as communities, opening a new branch of plant science that led later to the discipline of phytosociology, which is the classification of plant communities according to the characteristics and relationships of and among the plants within them.

Grisebach used this approach to divide the world into floral provinces. A floral province is a group of plants covering a large geographic area, all of which are adapted to the climate of that area. Grisebach shared the view of Humboldt, Lyell, Forbes, and others that plant communities had come into existence within the provinces where they were found, quite independently of events elsewhere. August Heinrich Rudolf Grisebach was born in Hannover, Germany, on April 17, 1814. He studied medicine and botany from 1832 to 1836, first at the University of Gottingen, where his uncle, Georg Friedrich Wilhelm Meyer (1782–1856), was a professor of botany, and later at Berlin, where he received his doctorate in medicine in 1836. In 1833, while still a student, he traveled in the European Alps studying the vegetation. After qualifying, Grisebach moved to Gottingen as a Privatdozent—a qualified academic who teaches without being paid by the university but receives payment from his students. In 1841, following his return from his travels through the Balkans and Turkey, Grisebach was appointed associate professor of botany within the medical faculty at Gottingen. He became a full professor in 1847, and in 1875 he was appointed director of the Gottingen botanical garden. Grisebach died at Gottingen on May 9, 1879.