Britannica Sources used in this answer

Which living plants belong to the lycophytes?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

lower vascular plant Aleutian maidenhair fern (*Adiantum aleuticum*) of the Pacific Northwest.

Lycophytes (class Lycopodiopsida) are a group of spore-bearing vascular plants represented today by more than 1,200 extant species. While they were once diverse, tree-sized plants during the Carboniferous Period, all living lycophytes are small, herbaceous plants.12

Under the Pteridophyte Phylogeny Group (PPG I) classification system, living lycophytes are categorized into three distinct orders:1

Club mosses (Order Lycopodiales): These are low-growing, evergreen herbs that produce a single type of spore (homosporous). The family Lycopodiaceae includes 16 genera, such as Lycopodium, Huperzia, and Lycopodiella.3
Spike mosses (Order Selaginellales): This order consists of a single genus, Selaginella. These plants are heterosporous, meaning they produce two different sizes of spores.4
Quillworts (Order Isoetales): This group includes the genus Isoetes and its allies.12

These plants are widely distributed globally, with the highest concentrations typically found in tropical regions.14