DIFFERENT REGIONS OF the Alps are made up of different kinds of rock. The western, southern, and northern Alps are calcareous, while the central part is acidic rock. From a botanical point of view, the northern limestone Alps, north of the Inn River in Austria, are more interesting than the areas with acidic rocks such as the central part of Tyrol. The hiker or the skier will not notice this, but the plant lover will be more satisfied in a limestone area. Interesting plants can be found throughout the growing season, and in the spring and autumn, you can walk from one botanical gem to another. The Tannheimer Valley, high in the northern Alps in Austria, is an ideal destination for a plant lover. It is only one mountain ridge away from Germany. One minute you are still driving in the rolling hills of the Allgäu and the next you are in a majestic mountain area filled with botanical treasures.