Abstract

The purpose of the present study was to determine the extent to which different morphological and reproductive characteristics of a critically endangered, Himalayan herb (Inula racemosa) varied along an altitudinal gradient. To this end, seven populations growing at different altitudes (1595 - 2800 m asl) across the Kashmir Himalaya were assessed. ANOVA expressed significant differences (P=0.05) in all growth parameters as a function of altitude. The highest difference between the populations was apparent in the stem height and in all populations patterns in the foliar and floral number and dimensions closely followed those in plant height. In four out of the seven populations, significant variation in floret number per head was detected among plants within all seven populations. Only 19-34% of variation was found within plants and in contrast 38-72% variation was found among plants. As compared to total ovule number per capitulum the species show low percentage of reproductive success (59-72% seed set). However, increasing altitude resulted in a decrease in relative and absolute allocation of biomass to reproductive structures in the form of decreasing dry weight of individual capitula as well as in the form of absolute declining of total number of capitula produced. There was also a trend for increased relative allocation to below-ground rhizome with increasing altitude, even though altitude did not affect absolute allocation to below-ground and vegetative structures.

Key words: Altitude, floral sex ratio, growth, Inula racemosa, phenotypic variability, reproductive success.