Botanic Gardens Conservation International (BGCI)
Botanical Garden Information System (SysTax)
List of botanical gardens (fact-index.com)
Botanical Garden Zagreb - links
Botanische Gärten (BioFinder, Kurt Stüber)
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Botanical gardens - Europe:
Rijeka > botanical garden
Botanical gardens - others:
Arnold Arboretum (Harvard)
Fairchild Tropical B.G. (Miami)