The vegetation of temporary ponds with Isoetes in the Iberian Peninsula

This study examines the floristical composition and the distribution pattern of the ephemeral quillwort swards found in the Iberian Peninsula. A systematic review based initially on 120 phytosociological releves and using numerical analyses with classification (Euclidean distance and UPGMA and MISSQ) and ordination (principal component ana­ lysis - PCA) was carried out. Four groups corresponding to the following associations were recognized: )unco pygmaei-Isoetetum velati, Peplido hispidulae-Isoete­ turn delilei,)unco capitati-Isoetetum histricis, Isoetetum durieui. The study supports previous assumptions that, on the local scale within the Iberian Peninsula, tem­ porary-pond plant-communities show greater diversity in western territories thus follo­ wing the same pattern that occurs on the regional scale of the Mediterranean basin.