374-Million-Year-Old Tree Trunks Reveal Unique Growth Strategy
Oct 26, 2017 by News Staff / Source
Massive, exceptionally well-preserved cladoxylopsid tree trunks found in Xinjiang, China, have revealed an interconnected web of woody strands (xylem) within the trunk of the tree that is much more complex than that of the living trees.
The xylem is responsible for conducting water from a tree’s roots to its branches and leaves. In the most familiar trees it forms a single cylinder to which new growth is added in rings year by year just under the bark. In other trees, notably palms, xylem is formed in strands embedded in softer tissues throughout the trunk.
Earth’s earliest trees (Cladoxylopsida) had their xylem dispersed in strands in the outer 5 cm of the tree trunk only, whilst the middle of the trunk was completely hollow, according to paleontologists who analyzed silicified trunks of the Late Devonian (374 million years ago) cladoxylopsid tree Xinicaulis lignescens.
http://www.sci-news.com/paleontology/cladoxylopsid-tree-trunks-unique-growth-strategy-05364.html
