A revision of Warnstorfia Loeske from the Iberian Peninsula has been undertaken based on examination of two hundred and four herbarium specimens. The following species are recognized for the Spanish bryological flora: W. exannulata (Schimp.) Loeske, W. fluitans (Hedw.) Loeske and W. sarmentosa (Wahlenb.) Hedenäs. W. exannulata is confirmed in Portugal and Andorra and W. fluitans is excluded from the checklist for Portugal and Balearic Islands.
All specimens determined in Iberian herbaria as Drepanocladus aduncus var. asturicus (Renauld) Riehm., D. exannulatus subfo. falcifolius Moenk., D. exannulatus var. alpinus (Grav.) Wijk & Margad. and D. fluitans var. falcatus (C.E.O. Jensen) G. Roth, have been re-identified as Warnstorfia exannulata.
Warnstorfia exannulata is common in the mountainous areas of the Eurosiberian and Mediterranean Regions of the northern and central part of the Iberian Peninsula, in three distinct areas: Pyrenees, Iberian-Atlantic Ranges (Galician-Portuguese Massif, Cantabrian Range, and Central Range), and Sierra Nevada (south Spain), although it is very rare in the latter. W. fluitans and W. sarmentosa are rare as both have higher moisture requirements than W. exannulata. Their distribution is limited to the mountains of the Eurosiberian Region of Spain, from the Cantabrian Range to the Pyrenees, where there is a strong Atlantic influence. The threats to Warnstorfia populations in the Iberian Peninsula are analyzed.