Archaeopteridales

Archaeopteris

First trees, first forests

Archaeopteris

Wood-producing ferns

Wood is a support tissue: the walls of sap-carrying cells are impregnated with a rigidifying substance known as lignin. The appearance of wood at the end of the Devonian (360 Ma), gave rise to numerous arborescent forms.

Archaeopteris, measuring 10 to 30 meters in height, is a “tree fern” that reproduced using spores; its wood, termed Callixylon, is identifiable by microscopic details of its cell ornamentation.

Archeopteris made up a significant part of the first forests to blanket the continents.