Botanical diversity is under high pressure in densilypopulated countries and protected areas play a veryimportant role in species conservation. In the Netherlands,borders of most nature reserves, includingNatura 2000 sites, have been drawn on the map before the 1990s.In the 1990s, long-term projects to collect observationdata of botanical diversity had just started to intensifyamong a community of volunteers united in FLORONPlant Conservation Netherlands, Dutch MycologicalSociety and the Bryological and Lichenological Society.Observation databases increased to around 40 millionrecords in 2019.Defining Important Plant Areas is a proven methodencouraged by the Global Strategy for Plant Conservationof the Convention for Biological Diversity and byIUCN’s Key Biodiversity Areas program.This report gives an overview of botanical biodiversityhotspots, regardless of their current nature conservationstatus, also providing insights of plant diversity ofurban and rural areas in The Netherlands.