Sawdonia ornata
Left: Reconstruction of the plant after Gensel & Andrews
(1984)
Right: Stem with the characteristic thin spines and the alternating
side branches.
Glasgow (Scotland). Lower Devonian. Height of the photo 14 cm.
The right hand photo clearly shows the structure of the plant. The axes are 3 - 10 mm wide (mostly 5 mm or less) and they show, like the previous plant, pseudomonopodial branching. The side axes are borne alternating left and right, growing at a rather sharp angle but soon bending till they grow nearly parallel to the main axis. It is striking that the main axis and the side branches are lie in one plane. This can be concluded from the fact that never a side branch lies over the main axis. The side axes are thinner than the main axis. The spines are generally thin, sometimes with a somewhat broader base.