They had cone-like reproductive structures rather like those of modern conifers. The Cordaitales appeared during the Carboniferous period. They made big trees which were common on drier ground in tropical environments.
Also, some tall trees and some shrubby mangrove-like species of Cordaitales seem to have grown in the Carboniferous coal swamps. Cordaitales were also abundant during the Permian, but died out at the end of the Permian.
- Eckenwalder, James E. 2009. Conifers of the World: the complete reference. Portland: Timber Press.