Collection of aquatic and wetland plants of the Institute of Botany of the Czech Academy of Sciences in Třeboň was established in 1976 by Š. Husák as a means to study the ecophysiology, ecological production, autoecology and taxonomy of endangered rare species. It contains about 350 macrophyte species. Most of the plants come from the Czech Republic, some from Central Europe and only about 10% are from other parts of the world. This collection, because of the number of macrophyte species, is the largest collection of aquatic and wetland plants in Europe and one of the largest in the world. It contains typical and also very rare plants of Czech flora and is used not only for basic research projects but also for protective cultivation that attempts to return some rare species to the natural sites. The collection also serves as a gene pool for rare and endangered plant species. It provides study and experimental material as well as material for species determination and botanical illustration. It is also used in the teaching of botany and plant ecology. Since 1998, 120-200 types of seeds are regularly listed on the Seed Index (Index Seminum).