Early land plant phytodebris

Historically, phytodebris (often considered a type of non-pollen palynomorph – NPP) has played a prominent role in research into the fossil record of early land plants. This phytodebris consists of cuticles and cuticle-like sheets, various tubular structures (including tracheids and tracheid-like tubes) and sundry other enigmatic fragments. Initial research focused on elucidating their morphology, attempts to identify them in situ in plant megafossils and comparisons with potentially homologous structures in extant plants. The fragmentary nature of these remains, and associated difficulties in positively identifying their presence in fossil/extant plants, resulted in vigorous debate regarding what many of these microfossils actually represented and their relevance to early land plant studies. More recently a wider array of analytical techniques has been applied (e.g. ultrastructural analysis, geochemistry and taphonomic experiments). However, positive identification of the affinities of at least some of these enigmatic fossils remained elusive. Ongoing investigations based on exceptionally preserved material from Lagerstätten (charcoalified and silicified) seem to have finally demonstrated that the more enigmatic of these remains derive from nematophytes that probably represent fungi and possibly also lichenized fungi.