About 35,000 herbarium sheets of mosses, ferns and above all flowering plants from all over Europe and overseas were created by more than 500 florists, especially in the 19th century, and united in a systematic collection in the years after 1960. The oldest records are several bound collections of native plants from the 17th and early 18th centuries, one of which is dated 1661. The herbarium also includes lichens, algae and fungi, fruits and microscopic specimens. The xylotheque, a collection of cut wood specimens, also represents a special highlight. It dates from the second half of the 18th century and goes back to the Erfurt merchant Johann Bartholomäus Bellermann.
The herbarium also includes the plant collection of the priest Friedrich Christian Heinrich Schönheit from Singen, who assembled a collection of 1232 species of the Principality of Schwarzburg-Rudolstadt for the Natural History Cabinet between 1837 and 1850. In 1850, Schönheit published his pocketbook of the Thuringian flora.
The herbarium contains evidence of the former occurrence of numerous species in Thuringia and beyond. About 70 % of the collection has been catalogued. Increased digitisation is being sought.