Morphology and infrared absorption spectra of fossil and modern Araucaria leaves. Top, examples of fossil (Araucaria carinata) and extant (Araucaria bidwillii) Araucariaceae showing the typical variation in leaf morphology within this group. Bottom, infrared absorption spectra of Araucaria haastii (fossil: Late Cretaceous period) and A. bidwillii (extant) recorded at three points on each cuticle sample showing correspondence of some absorption peaks. Note that the fossil cuticle typically contains fewer spectral features, for example, bands are lacking in the region 1,180–900 cm−1 indicating the absence of polysaccharides (cellulose, hemicellulose), but compounds incorporating aliphatic alkene/alkane (bands in the region around 3,000–2,800 cm−1 and 1,470–1,350 cm−1) and cyclic molecular structures (bands in the region around 1,600–1,350 cm−1) are retained. Note that the spectra have been shifted for clarity.