DRYOPTERIS Adans.-Shield fern, buckler fern, wood fern.

Plants terrestrial. Rhizome thick, suberect or erect, less commonly creeping, surrounded by close, spirally arranged leaves and old leaf bases; rhizome scales nonclathrate. Leaves usually in a rosette; stipe grooved, scaly, with 3-7 (9-10) vascular bundles arranged in a C-shaped pattern; blades 1-4 times pinnately compound, bearing scales but lacking needlelike hairs, the pinna midribs grooved. Sori round, dorsal; indusium kidney-shaped, attached at a sinus, rarely absent.

The genus of ca. 225 species is cosmopolitan, occurring mostly in temperate forests and montane areas of the tropics. The species are difficult to identify simply because there are so many of them, and there are many similar groups of species. Furthermore, the fronds can vary even on the same plant. Identification requires careful examination of large, mature leaves. About 50 species are in cultivation in the United States, but new species are constantly being added to the trade and older ones are disappearing.

The species of Dryopteris pose no special problems in cultivation, except that some of the species native to colder climates do not adapt well to warm-climate gardens and some species thrive only in acidic soils. Most species are easy to propagate from spores or divisions. Offshoots come from the base of erect rhizomes, semi-erect rhizomes or branches of short-creeping rhizomes. Generally, species that are deciduous in cold temperate climates tend to be more evergreen in warmer climates. Fronds that become deciduous wither in place but may or may not promptly lose their green color.

The groups used in this treatment are the subgenera and sections of Dryopteris recognized by Fraser-Jenkins (1986).