Figure 4

Partial ion chromatograms. The Py-GC-MS analysis of modern Phragmites australis culms and leaves and ancient Phragmites culms showing the distribution of (black circle) Polysaccharide, (black square) lignin, (black rhombus) fatty acid, (black star) amino acid, and (black triangle) n-alkanes. The “S,” as in S7, stands for “Site.” See Data S2 for compound identifications.