What it is
A cone-bearing seed plant with a stout trunk and a crown of stiff fronds. The sago palm sold in garden centers is a cycad, not a palm at all. About three hundred species are alive today.
An old family
Cycad fossils turn up in Permian rocks, older than the first dinosaurs. In 1969 the paleobotanist S. H. Mamay described Permian plant fossils from the southwestern United States as cycad seed-leaves, which pushed the family's record back from the Late Triassic into the Paleozoic. Cycads were at their most varied in the age of dinosaurs, then dwindled as flowering plants took over.
Young species
In 2011, scientists compared the genes of about two hundred living species. Most of today's species, they found, came from bursts that began about twelve million years ago, on several continents at about the same time. Later, larger studies put the starts between about eleven and twenty million years ago, and a few lone lineages are much older.