Palmenkas (Hortus Botanicus Amsterdam)

Built in 1911–1912 by architect Johan Melchior van der Mey in the expressionist style of the Amsterdam School, the Palmenkas was erected at the request of the garden's board to persuade Professor Hugo de Vries to remain at the head of the Hortus. Beneath its dome of iron, stone and glass grows an Encephalartos altensteinii about 350 years old, one of the oldest potted plants in the world. The greenhouse also holds trees said to have been planted by De Vries himself, including a cinnamon tree, along with an imposing Philodendron bipinnatifidum with spectacular aerial roots.