We know that ferns were around with the dinosaurs, based on fossil records, and are little changed today. Other plants, the so-called fern allies, also hail from that age and are botanically distinct from the flowering plants that evolved later.
Scouring-rush (Equisetum hymale) does not grow naturally at this preserve (though it can be found nearby at our Stone Hills Preserve). The common name is hyphenated above, implying that it is not a true rush, though perhaps it resembles one. Its leafless stems are filled with an abrasive silica--at one time they were used for scouring pots and pans. I planted some in my garden as a curiosity, a gift from a fellow gardner. She didn't tell me how much it spreads! I wish I'd planted it in a sunken container to confine it. You've been warned.
Field horsetail (Equisetum arvense) is closely related, but is branched into fine leafless stems, making it look grassy or hairy. It is common in wet fields and roadside ditches, where it can be found at Crow's Nest. These fern allies do not flower and set seed; like a fern they release single-celled spores that grow into a tiny organism called a gametophyte, where the reproductive processes analagous to a flower's take place.