Arrangement of the Herbarium

With perhaps 450,000 specimens, it is crucial that our specimens are stored in a way that means they can be quickly and reliably accessed. Our specimens are first organised by major group (algae, bryophytes, lichens, vascular plants) with different systems in each group.

Cabinets in the world flowering plant herbarium in Trinity College Dublin.

The British and Irish vascular plant collections were the first collections to be reordered into a modern system and now use the APG III linear arrangement. In summer 2026, we reorganised our world flowering plant collections into a modified version of the APG IV system. Within families, the specimens are further divided by genera, then by geography, and finally by species.