EN
The paper includes results of measurements of the length and diameter of 12600 acorns of Quercus robur and 5099 acorns of Q. petraea collected in Poland in the mast-year 1993. Acorns of both species were compared. Significant differences in acorn length and diameter/length ratio were found. Acorns of Q. robur are somewhat larger, but both species have a large common area of variability. The scale of this variability has been determined. Geographical correlation of the size of Q. robur acorns was ascertained.