Equisetum - Scouring Rush Is The Oldest Extant Genus Of Land Plant?
Over 100 million years ago, late Mesozoic forests were chock full of a diverse group of plants of the class Equisetopsida, though only one genus, Equisetum, commonly called scouring rush or horsetail, still exists today.
It is unclear about the evolutionary beginnings of the genus Equisetum - molecular dating places the divergence of the 15 extant species of the genus around 65 million years ago but the fossil record had it earlier than that, around 136 million years ago.
A new fossil Equisetum species now places this genus at 150 million years ago and living in an environment where…