Conifers
Conifers (order Coniferales) are woody trees or shrubs with their reproductive structures arranged in compound or simple cones. They play a dominant role in a diversity of terrestrial biomes on six continents, and left a fossil record in Antarctica before going extinct. The modern diversity of conifers is estimated at six families, 70 genera, and 630 species. Extant species diversity can be attributed to a combination of relicts and recent radiations. The conifer fossil record extends to the Carboniferous (ca. 299-318 million years ago), and modern families appear to have diversified long ago.
Families
Pinus cembroides, Sierra de Organos, Zacatecas.
Araucariaceae (3 genera, 41 species)
Cupressaceae (31 genera, 173 species)
Pinaceae (11 genera, 238 species)
Podocarpaceae (19 genera, 173 species: includes Phyllocladaceae)
Sciadopityaceae (1 genus, 1 species)
Taxaceae (6 genera, 28 species: includes Cephalotaxaceae)
For more information
Quinn, Price and Gadek (2002). Familial concepts and relationships in the conifers based on rbcL and matK sequence comparisons. Kew Bulletin 57:513-531.
Farjon (2001). World Checklist and Bibliography of Conifers, Second edition. Royal Botanic Gardens, Kew.