Division Pteridophyta, also known as the Filicinophyta, is a group of plants that reproduce via spores. Commonly referred to as ferns, this division includes over 12,000 species with a wide range of growth forms, from small epiphytic herbs to large tree ferns. Some synonyms for Pteridophyta include "Filicopsida," "Polypodiophyta," and "Pteropsida." Filicopsida is used to differentiate ferns from other spore-producing plants, while Polypodiophyta is used to refer specifically to the subphylum of modern ferns. Pteropsida is used to refer to all seedless vascular plants including ferns, lycophytes, and horsetails.