Valentin Plemel was the first Slovenian botanist who furnished his herbarium with more or less complete labels with the most pertinent information. His only published treatise Contributions to the Carniolan Flora (1862) was written in German and is the third printed work on the flora in the Slovenian territory. In the 1839-1875 period, he generated a sizeable herbarium. He collected plants near the places where he studied and worked: in the region of Gorenjsko, in the vicinity of Ljubljana, Ilirska Bistrica, and the regions of Kočevsko and Dolenjsko. In 1873, he received the Progress Medalat the World Exhibition in Vienna for his Herbarium of Carniolan Plants. Valentin Plemel was also the first Slovenian botanist to furnish part of the herbarium with labels written in the Slovenian language. In August 1843, he collected a specimen of the Great Sundew (Drosera longifolia) at “Rečiškim Križanci v Bledu na Gorenskim”, and signed it V. Plemel Rečičan. This is the oldest herbarium sheet written in Slovenian. The bulk of his herbarium is housed in the Slovenian Museum of Natural History, while a smaller part is stored in the collection of the University of Ljubljana at the Department of Biology. His herbarium, meticulously collected, defined and furnished with all possible data, was a source of information for numerous botanists later on.