Other Fern Allies

This group gathers Ferns and Fern Allies subcategory members that are genuine ferns or fern allies but that this atlas's own sourced descriptions do not identify with one of the seven more specific groups gathered separately above. Its one member, the quillwort, is a lycophyte of the genus Isoetes and family Isoetaceae, an unusual, mostly aquatic or semi-aquatic plant that grows a dense tuft of narrow, quill-like leaves from a short, bulbous stem, closely related to the clubmosses and spikemosses gathered elsewhere in this atlas but distinct enough in both form and evolutionary history to warrant its own family rather than folding into either. Every member gathered here is a genuine fern or fern ally by the broad definition this atlas uses for the subcategory; the split above exists only to keep seven especially large or well-known groups browsable on their own rather than to draw a biological line excluding anything placed here.