Whisk Ferns (Psilotum)

This group gathers Ferns and Fern Allies subcategory members belonging to the genus Psilotum, the whisk ferns, an unusual and structurally simple group of vascular plants notable for possessing neither true roots nor true leaves of any kind, a striking departure from nearly every other plant gathered elsewhere in this atlas. A whisk fern's green, repeatedly forking stem carries out photosynthesis directly, in place of the broad leaf surface most plants rely on, and the plant absorbs water and nutrients through a symbiotic fungal partnership at its base rather than through a conventional root system. Long classified as one of the most primitive living vascular plant lineages on Earth, molecular studies have more recently placed the whisk ferns as a highly simplified, secondarily reduced relative nested within the true ferns rather than as a truly ancient, separate branch of plant evolution, a genuinely surprising revision to how the group's place in the plant family tree is understood.