Previous investigations of sporopollenin using13C Solid State Nuclear Magnetic Resonance have demonstrated differences between the major groups of plants in the composition of this acetolysisresistant biomacromolecule. The work presented here corroborates these results and suggests that sporopollenin obtained from seed megaspore-membranes differs slightly from that of pollen from the same plant group. Spectra obtained using NMR have been subjected to multivariate analysis. This approach has provided information which may be interpreted in phylogenetic terms. A number of fossil sporopollenins have also been investigated. These all show considerable degradation through diagenesis but retain certain characteristics of the original sporopollenin composition. Microspores and megaspores from the same species of Carboniferous arborescent lycopsid have also been investigated with a view to discerning any differences in composition that may exist between these sources of sporopollenin in the fossil record. Investigation of the effects of acetolysis on spore walls has also been undertaken. Together with the above work, this contributes to our understanding of the chemical composition of sporopollenins and the way in which this substance is affected by a treatment commonly used in the preparation of exines.