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Alpine plants growing along altitudinal gradients have been traditionally considered to have reduced flowering and growth and enhanced clonality toward higher altitudes. This pattern, however, has seldom been studied for multiple characteristics in one plant species and over several years, and thus its generality is uncertain. In the present study, we used annual growth markers on perennial rhizomes (herbchronology) to analyze the long-term growth of Rumex alpinus. By determining the width and length of rhizome segments (annual increments) and the numbers of leaf scars, inflorescence scars, dormant buds, and branches preserved on rhizomes, we analyzed past growth for more than 10 years at seven sites along an altitudinal gradient (950-1,900 m a.s.l.) in the Low Tatra Mts., West Carpathians, Slovakia. We determined where growth was optimum on the gradient and whether the data supported the common opinion that clonal growth is enhanced and flowering is reduced with increasing altitude. Although R. alpinus is a light-demanding species occurring preferentially along small streams above the treeline, the most vigorous growth (highest number of leaves and inflorescences) occurred at low altitudes in forest clearings. According to expectation, R. alpinus exhibited less flowering and growth but increased clonality with increasing altitude. Low temporal inequality in growth indicates that the perennial rhizome system plays a role in buffering year to year climatic variability in the harsh environment along altitudinal gradients. [ABSTRACT FROM AUTHOR]