Six clonal lines of intermediate wheatgrass, Agropyron intermedium (Host.) Beauv., which differed markedly in gross morphological characteristics were cut at the half-bloom stage and separated into leaf and stem. Lignin analyses were made on both leaf and stem in 1951 and again in 1952.Analysis of variance established significant differences (P = 0.05) in per cent lignin content between clonal lines. Highly significant differences (P = 0.01) were found in per cent leaf between lines and in per cent lignin between years. The plants contained the most lignin in the driest year.The clonal line with the finest stems had the lowest lignin content; however, the percentage leaf had a greater effect on lignin content than any other factor studied.