Chemotaxonomy of Some Paleozoic Vascular Plants. Part I: Chemical Compositions and Preliminary Cluster Analyses

Abstract

The chemical compositions of plant fossils having trimerophyte (Pertica,Psilophyton princeps, P. cf.jorbesii), rhyniophyte (Taeniocrada), and zosterophyll (Sawdonia) morphological characteristics are chemically analyzed and chemotaxonomically related to vascular ( ?Eohostimella, Renalia, Chahuria) and putative non-vascular plant fossils (Botryococcus, Parka, Pachytheca, Prototaxites,Nematothallus, Spongiophyton, Protosalvinia, Orestovia) whose taxonomic affinities are unknown or speculative. Separation of the material examined into clusters representing higher taxa (i.e., algal, nonalgal, trimerophyte, rhyniophyte, zosterophyll plant groupings) is effected by the weighting of chemical data during cluster analyses. The weighting of phenolic and monohydroxycarboxylic acid constituents is shown to cluster vascular plant material, while the criteria of carbon chainlength ranges and maxima separate vascular from non-vascular plant fossils. Multivariate analysis of the data, using chemical and geological factors, results in the clustering of four groups: (1)Botryococcus, Parka, Pachytheca, (2)Spongiophyton, Prototaxites, Nematothallus, Orestovia, (3)Eohostimella,Taeniocrada, Renalia, and (4)Psilophyton spp.,Pertica, Chaleuria. Sawdonia andProtosalvinia appear as data points showing no observable affinity with any of the above fossils.Protosalvinia, Renalia, andChaleuria are interpreted as being chemotaxonomically intermediate. These data are interpreted as indicating taxonomic affinities on a very broad scale ; possible evolutionary trends in specific chemical compounds, as they relate to vascular and non-vascular plant geochemistry, are discussed.