Gums and resins “exuded” by seed-bearing plants (Gymnosperms) are compositionally distinct, and can be diagnosed using infrared (IR) spectroscopy. Ralf Tappert and colleagues used IR spectroscopy to distinguish the resin produced by pine trees (Pinaceae) from other conifers, and provided identities for gums and other resins as well. Exuded resin hardens into amber and survives through geologic time. Tappert et al. (2011) have therefore provided a method for identifying fossil pine forests.
Tappert R, Wolfe AP, McKellar RC, Tappert MC and Muehlenbachs K (2011). Characterizing Modern and Fossil Gymnosperm Exudates Using Micro-Fourier Transform Infrared Spectroscopy. International Journal of Plant Sciences 172: 120-138.
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