Herbarium is a biological collection of plant (and fungi) specimens with relevant information on attached labels that provide details of where and when the specimen was collected, ecological information and habitat, as well as the name of the collector. The specimens are housed in special cabinets and arranged according to standard biological classification. The material is carefully prepared to withstand handling and the passing of time. A plant specimen (the whole plant or part of it) is pressed and dried between sheets of paper and fixed with sticky paper tapes on good stiff paper together with its label.
Herbaria are known and cited by their international acronyms (Thiers, B. (2017): Index Herbariorum. A global directory of public herbaria and associated staff. New York Botanical Garden’s Virtual Herbarium) – Herbarium Croaticum (ZA) and Herbarium of Ivo and Marija Horvat (ZAHO) are the two herbarium collections of the Department of Biology, Faculty of Science, University of Zagreb.
ZA has c. 300,000 specimens, organised in separate collections according to general systematic units and the geographical provenance of stored herbarium material. The main organisational collections are:
- Herbarium Croaticum – the core collection of the ZA Herbarium includes the largest collection of Croatian plants anywhere. The collection retains the original organisation of the herbarium and is by Dalla Torre’s Genera siphonogamarum of 1900-1907 (Gen. siphon.).
- The General Collection – Croatia’s largest collection of plants from the whole world. The organisation of the collection follows Ludovico Pfeiffer (1870): Synonymia botanica locupletissima generum, sectionum vel subgenerum ad finem anni 1858 promulgatorum: In forma conspectus systematici totius regni vegetabilis schemati Endlicheriano adaptati.
- Bryophytes – The collection includes herbarium specimens from Croatia and nearby region. The Bryophytes are organised alphabetically.
- Lichens - The collection includes herbarium specimens from Croatia and other parts of the world. The Lichens are organised alphabetically.
- Fungi - The collection includes herbarium specimens from Croatia and other parts of the world. The Fungi are organised alphabetically.
- Algae - The collection includes macrophytic algae from Croatia. The Algae are organised alphabetically.
ZAHO collection has 71,611 herbarium specimens collected by prof. Ivo Horvat and organized by his wife Marija. The collection includes Cryptogams and vascular plants, mainly from Croatia and other Balkan countries. The respective collections are organised alphabetically by families.