Ferns & Fern Allies
This is an evolutionarily ancient and very diverse group of plants that are often placed together in the taxonomic Division Pteridophyta, which is comprised of vascular plants that do not produce seeds, but instead reproduce through spores. Pteridophytes have two functional life stages, a free-living, independent gametophyte stage that produces motile sperm and a sporophyte stage (which is the stage we see, in the form of fronds and stipes). The morphological and evolutionary diversity contained within this division of the plant kingdom is considerable.

In Denali the “lower plants” in Division Pteridophyta are represented by the following groups: true ferns (Blechnaceae, Dryopteridaceae, Pteridaceae, Thelypteridaceae, and Polypodiaceae) the horsetails (Equisetaceae), Club mosses, (Lycopodiaceae), Spike mosses (Selaginellaceae) and quillworts (Isoetaceae).The most species-rich fern family in the Denali flora is the Wood fern family (Dryopteridaceae; 13 species), followed by the Maidenhair fern family (Pteridaceae; 3 species). There is one species each from the three other fern families that occur here: Deer fern family (Blechnaceae), Polypody family (Polypodiaceae), and Marsh fern family (Thelypteridaceae).

Closely related to the true ferns are an ancient and peculiar-looking group of spore-bearing plants appropriately called the Moonworts, which are placed by taxonomists in the Adder-tongue plant family (Ophioglossaceae). There are ten species of moonworts known to occur in the flora of Denali National Park and Preserve. Except for the most common member of this genus in the park, which is Botrychium lunaria, these species have very interrupted and spotty distribution patterns – they are found only rarely, even by the keenest observers. Moonworts are most commonly found in lush and moist, (but not wet) meadow habitats in subalpine slopes and river terraces in association with dense growths of grasses such as Festuca altaica, Poa spp. and forbs, including wild geranium (Geranium erianthum), monkshood (Aconitum delphiniifolium) and veronica (Veronica wormskjoldii).
Of the 28 fern and fern ally species occurring in the park, 22 species are included in the atlas.