Although a few can be assigned to the modern genus Pinus , most are placed in the fossil genus Pityostrobus because they combine characters not found in modern taxa. Other modern pinaceous genera evolved during the Tertiary. Look at specimens of Pinus ovulate cones, stems and leaves from the petrified Princeton Chert, and at the compressed Miocene pine needles from Creede, Colorado. The Taxodiaceae are another good example of a family of plants that was widely distributed and common in the Cretaceous and Tertiary, that has a much more restricted distribution today. These plants are monecious trees with leaves that are spirally arranged or opposite, needlelike or linear.
Pollen is nonsaccate.
The fossil record of the Taxodiaceae extends from the Jurassic to the Recent. Fossil representatives are plentiful especially in the Cretaceous when Metasequoia was widespread and represents the dominant foliage type in many localities, particularly in northwestern North America. Look at compressed Metasequoia foliage from the Cretaceous of Alaska and at the paper by Serbet and Stockey on cones from Drumheller, Alberta. A fossil family, the Cheirolepidaceae, which may be transitional between the Voltziales and Taxodiaceae is important from the Triassic through the Cretaceous in Europe and Argentina. This family is a good example of the greater degree of conifer diversity that occurred during the Mesozoic.