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We used pollen analysis to evaluate the territories and the northermost slopes of the Cantabrian-Atlantic Mountains). During these dynamics of sclerophyllous arboreal taxa during the last 16,000 years. Quercus ilex type pollen and, to a periods, there is no indication of the presence of Quercus ilex pollen in the northwestern territories, which would lesser degree, other sclerophyllous elements (e.g. Olea and Phillyrea) have been documented during the Late-explain the absence of this species in the present-day landscape. Despite the widespread distribution that glacial in the majority of the sequences obtained in continental territories in the north of the Iberian sclerophyllous elements have maintained during the last 16,000 years, they have never attained a peninsula, as well as in the eastern coastal/sub-coastal area in the Cantabric region. During the Late-glacial predominant role in the landscape, having a smaller representation, both during hotter and colder phases, and the Holocene, sclerophyllous elements became widespread in many areas of the north Iberian than deciduous forests, pine forests and mixed forests. peninsula (the Sil, Duero and Ebro depressions and the southernmost slopes of adjacent mountains), with Key words. Iberian peninsula, sclerophyllous forests, Quercus ilex, species range, Late-glacial, the smallest pollinic representation of these taxa being for the most septentrional areas (coastal/sub-coastal Holocene, vegetation history, palynology.

We used pollen analysis to evaluate the dynamics of sclerophyllous arboreal taxa during the last 16,000 years. Quercus ilex type pollen and, to a lesser degree, other sclerophyllous elements (e.g. Olea and Phillyrea) have been documented during the Late‐glacial in the majority of the sequences obtained in continental territories in the north of the Iberian peninsula, as well as in the eastern coastal/sub‐coastal area in the Cantabric region. During the Late‐glacial and the Holocene, sclerophyllous elements became widespread in many areas of the north Iberian peninsula (the Sil, Duero and Ebro depressions and the southernmost slopes of adjacent mountains), with the smallest pollinic representation of these taxa being for the most septentrional areas (coastal/sub‐coastal territories and the northermost slopes of the Cantabrian‐Atlantic Mountains). During these periods, there is no indication of the presence of Quercus ilex pollen in the northwestern territories, which would explain the absence of this species in the present‐day landscape. Despite the widespread distribution that sclerophyllous elements have maintained during the last 16,000 years, they have never attained a predominant role in the landscape, having a smaller representation, both during hotter and colder phases, than deciduous forests, pine forests and mixed forests.

An analytical RPLC method for sesquiterpene lactones in Arnica montana has been extended to include quantitative analyses of dihydrohelenalin esters. LC-ESI-MS-MS distinguished the isomeric helenalin and dihydrohelenalin esters. The dihydrohelenalin esters have lower response factors for UV detection than do helenalin esters, which must be taken into account for quantitative analyses. Analyses of flowers from 16 different wild populations of A. montana in Spain showed differing proportions of helenalin and dihydrohelenalin esters. For the first time a chemotype with high levels of helenalin esters (total helenalins 5.2-10.3 mg/g dry weight) is reported in Spanish A. montana. These samples were from heath lands at high altitude (1330-1460 m), whereas samples from meadows and peat bogs at lower altitudes were the expected chemotype with high levels of dihydrohelenalin esters (total dihydrohelenalins 10.9-18.2 mg/g). The phenolic compounds, both flavonoid glycosides and caffeoylquinic acids, in Spanish A. montana are reported for the first time. The levels of several of these compounds differed significantly between samples from heath lands and samples from peat bogs or meadows, with the heath land samples being most similar to central European A. montana in their phenolic composition.

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