Small and in-country herbaria are vital for accurate plant threat assessments: A case study from Peru

center dot Internationally agreed targets to assess the conservation status of all plant species rely largely on digitised distribution data from specimens held in herbaria. center dot Using taxonomically curated databases of herbarium specimen data for the mega-diverse genera Begonia (Begoniaceae) and Solanum (Solanaceae) occurring in Peru, we test the value added from including data from local herbaria and herbaria of different sizes on estimations of threat status using International Union for Conservation of Nature (IUCN) Red List criteria. center dot We find that the Global Biodiversity Information Facility (GBIF) has litter data from Peruvian herbaria and adding these data influences the estimated threat status of these species, reducing the numbers of Critically Endangered and Vulnerable species in both genera. Similarly, adding data from small- and medium-sized herbaria, whether in-country or not, also improves the accuracy of threat assessments. center dot A renewed focus on resourcing and recognising the contribution of small and in-country herbaria is required if we are to meet internationally agreed targets for plant conservation. We discuss our case study in the broader context of democratising and increasing participation in global botanical science.