Rediscovering <i>Carduncellus matritensis</i>: assessing the conservation status of an Iberian endemic

Abstract The plant Carduncellus matritensis (Cardueae, Compositae) was formerly known from only a single locality: Cerro Negro in Madrid Province, Spain. It is one of the six endemic species Spanish flora considered to be extinct. causes its presumed extinction were anthropogenic: growth city subsumed locality into city, such that now railway station. During 2021–2022 we discovered three new populations c. 50 km south type locality, with 130–166 mature individuals. Habitat fragmentation and degradation are most significant threats facing populations. We categorize conservation status as Critically Endangered according IUCN Red List criteria. To avoid loss this species, recommend both situ (creation micro-reserves) ex (seed storage) measures.