Sphagnum lindbergii Schimp.: a new peat moss species to the Iberian Flora

Sphagnum lindbergii Schimp., a moss species of circumpolar distribution, is reported for the first time in Spain and in the Iberian Peninsula. This discovery, made in the chalybeate springs in the Chistau Valley (Central Pyrenees), adds to the only Pyrenean population currently known, limited to the French Rioumajou Valley. The Spanish population comprises four small patches occupying an estimated 5 m². We describe its morphology, emphasizing diagnostic traits, and its habitat, characterized by iron-rich flushes in acidic, sub-alpine environments. The population faces significant threats, including livestock trampling and climate change, prompting its classification as Critically Endangered (CR) following IUCN criteria. Conservation measures are urgently recommended given its extreme rarity in the Pyrenees.