1) Chiefly terrestrial ferns 2) Fern genus 3) Genus dennstaedtia 
Dennstaedtia is a primarily tropical genus of ferns with some 59 species (some say 80 species). Its best-known member is probably the temperate North-American hay-scented fern (pictured in the taxobox), which forms extensive clonal ground-cover colonies on level surfaces in the Appalachian area. Full list of Dennstaedtia species: http://homepages....
(from the article `fern`) ...ferns, the rhizome short to long and creeping; indument of hairs, rarely scales; sori mostly marginal with 2-lipped indusia; spores mostly ...
[n] - chiefly terrestrial ferns
genus Dennstaedtia noun chiefly terrestrial ferns; in some classification systems placed in family Polypodiaceae