The land plant cover in the Devonian: a reassessment of the evolution of the tree habit

Abstract

This paper reviews information on the Devonian trees that evolved in the euphyllophyte clade with special focus on the Middle Devonian Pseudosporochnales. The morphology of pseudosporochnalean trees shows analogies with that of extant tree ferns, including the possession of an adventitious root system of limited extent at the base of the trunk. Direct evidence on how these trees were constructed is scarce. We propose a growth model integrating information from younger representatives of the same class known to reach large diameters. According to this model, trunk width in its aerial part results from the large size of its primary body where living tissues are abundant, a condition reached early during growth. Secondary xylem contributes little to trunk diameter. This model sharply diverges from that of the Late Devonian archaeopteridalean trees characterized by an extended root system and where trunk diameter and mechanical support are achieved by the substantial development of secondary vascular tissues. These differences suggest that pseudosporochnalean trees may have had a lesser impact on Devonian environments than the Archaeopteridales. The important investment in living tissues in the Pseudosporochnales probably made them vulnerable to drought and cold.

Molecular proxies as indicators of freshwater incursion-driven salinity stratification

“…Whilst an origin from quinone pigments in marine fungi (mainly lignin degraders) or crinoids cannot be excluded, its abundance in the Devonian samples observed here, which coincides with the evolution of the first woody plants and formation of forests (Meyer-Berthaud et al, 2010), points to a likely terrigenous source. Higher plant input was additionally confirmed by palynological and other microscopic evidence which included comminuted plant debris, resin bodies and microfossils from progymnosperms (see Tulipani et al, 2014).…”

Late Devonian plant communities of North Russia

“…This resulted in many publications on their morphology, anatomy, palaeoecology, etc. (Beck, 1960;Snigirevskaya, 1984, 2012Meyer-Berthaud et al, 2010 Comparison of the Late Devonian floras of NT with several surrounding ones is based on the analysis of archaeopterideans. We found that all above-described floras of NT contain various archaeopteridean remains.…”

Pennsylvanian ‘fossil forests' in growth position (T 0 assemblages): origin, taphonomic bias and palaeoecological insights

“…The situation becomes stranger, the further back in time we retreat. The recent discoveries of weird 'trees' in Devonian strata, including arborescent fungi (Boyce et al 2007) and cladoxylopsids (Stein et al 2007;Meyer-Berthaud et al 2010), well illustrates this point.…”