The class Sphenopsida is an ancient one, much more well-represented in fossil history than in present-day plants. The sole surviving genus is Equisetum, with only a few species.
I have placed the Equisetums, the psilotoids, and the ophioglossoids together in the division Archeophyta because there are studies that show that they may have an ancient common source after the divergence of true ferns and lycopods. They are probably closer to the seed plants than these other groups, but may be slightly more closely related to each other, representing a phyletic, though distantly-related, group.
Classes of Archeophyta:
Top of Page
Feedback
This page was last revised on 11-10-1997.