IndExs – Index of Exsiccatae

IndExs – Index of Exsiccatae is an online biological database that plays a pivotal role in documenting more than 2,200 historical and ongoing series of exsiccatae and exsiccata-like works. Managed by the Botanische Staatssammlung München in München, IndExs serves as a comprehensive data repository for these series, providing detailed titles with information on the more than 1,300 editors, bibliographic information, exsiccatal numbers, publication timespans, ranges, information on preceding and superseding series and publishers. Exsiccatae, organised series of biological specimens distributed among biological collections, are essential resources found in major herbaria worldwide. Open access to the general information on exsiccatae facilitates global scientific engagement and research.

History and purpose
Launched in 2001, IndExs has become indispensable to herbaria, fungaria, and digitisation initiatives, catering to their evolving scientific content needs. The database categorises exsiccatae and the specimens they distribute, focusing on major organismic groups within botany and mycology. This categorisation is enhanced by images of exemplary specimen labels from more than 70 herbaria citing their Index Herbariorum´s acronyms. IndExs standardizes the naming conventions for exsiccata series.

IndExs leverages the DiversityExsiccatae module of the Diversity Workbench framework as database management system. Recently, efforts to align its technical infrastructure with Wikidata concepts have begun, indicating a move towards more integrated and semantic web-based data management practices. The main focus is on the disambiguation of names of more than 1,300 editors and the integration of information for 2,200 exsiccata series into the semantic web. This move involves adopting Wikidata identifiers for the precise identification of editors, contributing additional details to existing Wikidata entries about their scientific work, and creating new entries where necessary. A proposed new property, the "IndExs Exsiccata ID," aims to link directly to IndExs, allowing for the incorporation of exsiccata series information into Wikidata. This integration facilitates a linked data environment, ensuring that the significant contributions of botanical and mycological editors and their work are more accessible and accurately represented in global data repositories.

Applications
The practical application of IndExs is highlighted by its use in the cataloguing and analysis of the bryophyte collection at the National Herbarium in Pretoria (PRE), South Africa. In this project, IndExs was used to compile the first catalogue of exsiccatae for the PRE collection and provided the necessary framework and reference material to identify and classify the 66 exsiccatae series represented in the collection. Through IndExs, the project team was able to identify and document significant exsiccatae within the PRE collection, including rare sets like Anton Rehmann's Musci Austro-Africani and Bryophyta Antarctica exsiccata edited by Ryszard Ochyra. This case shows how IndExs facilitates the documentation and study of botanical specimens, enabling the first comprehensive catalog of exsiccatae within a major herbarium collection. Through IndExs, researchers can access information on exsiccatae, contributing to botanical research, taxonomy, and the history of botanical exploration and exchange. Similarly, the IndExs has been proposed for use as a reference list in the digitisation of German herbaria specimens and related biodiversity informatics projects.