EN
Positive correlation between seed weight and germination capacity is common for the vast majority of species. It is also known that seed weight can vary along a latitudinal gradient. The seed mass of the invasive Himalayan balsam (Impatiens glandulifera), which is native to East Asia, was examined in relation to distinct geographical regions in Poland (Bielsko-Biala: N49°52′32″, E18°57′43″; Katowice: N50°12′8.3″, E18°57′26″; Tworków: N50°01′22″, E18°15′28”); Hungary (Rum: N47°06′41″, E16°50′45″; Rábahídvég: N47°03′54″, E16°44′59″) and Germany (Halle: N51°28′47″, E11°57′12″; Marburg: N50°48′32″, E8°46′31″). The study revealed that seed mass varied both among the countries and among specific populations within Poland and Germany. In Hungary, the 50 seed lots were the lightest 0.29 g and 0.31 g in respective localities and the heaviest in single populations in Poland – 0.61 g and in Germany – 0.57 g. In the present study, populations located more southwards had the lightest seeds in contrast to the commonly encountered pattern. Higher temperature, lower precipitation and as a consequence, a shortage of water can be crucial factors that affect the seed mass of I. glandulifera. Taking into account the lower frequency and abundance of the species in Hungary, the lower seed mass may probably contribute to the limited distribution range in this region.