Whisk Fern, Psilotum nudum
The Whisk Fern (Psilotum nudum), is a genus of fern-like vascular plants, one of two genera in the family Psilotaceae, order Psilotales, and class Psilotopsida (the other being Tmesipteris). The distribution of Psilotum is tropical and subtropical, in the New World, Asia, and the Pacific. The highest latitudes known are in South Carolina and southern Japan for P. nudum. In the U.S., one species is found from Florida to Texas, the other in Hawaii.
They had traditionally been thought not to be true ferns, but rather, odd primitive vascular plants similar to the fossil rhyniophytes and psilophytes. In addition, they lack true leaves and roots (like the Bryophytes), and thus represent the simplest of vascular plants, albeit whose simple features are the apparent reduction from more complex evolutionary predecessor. They do however have stems and rhizoids.