Marginal Shield Fern

Appearance

''Dryopteris marginalis'' is an evergreen fern throughout its range, along with Christmas fern it is one of the few evergreen ferns. Marginal wood fern grows from a clump with a prominent central rootstock, this rootstock may be exposed and give this fern the appearance of being like a small tree fern. Often, the dead leaves will accumulate beneath the plant. The stipe, or stem which supports the leaf is approximately 1/4 the length of the leaf and covered in bright golden brown scales. The stipe itself is grooved on the upward-facing side and dark red-brown at the base and becoming green further up the leaf.

The leaf is a dark blue-green and thick and leathery in texture. It grows 1–2 ft in height and approximately 6 in wide. Each leaf is broken up into leaflets which are arranged on either side of the main stalk. The tips of these leaflets are generally curved toward the tip of the leaf. These leaflets themselves are divided into subleaflets which are blunt-tipped and either serrated or lobed. The fertile leaflets are similar to the fertile leaflets in size and appearance. The round sori are located on the margins of the leaf tissue. Before the sori are ripe they start gray then they turn an interesting blue-violet color before finally turning brown when they are mature. The sori are covered in a kidney-shaped indusium which is smooth.

Distribution

''Dryopteris marginalis'' has a wide distribution in the northeastern USA. It was found for the first time in Minnesota in 1981, and likely was part of the native flora for a long time but overlooked because of its rarity and its close resemblance to related species. It is listed as a threatened species in Minnesota, not so much because the species is currently threatened, but because there is only one population found on an east-facing bluff composed of sandstone that is capped with limestone. In other parts of its range it is found in woods, on talus-slopes, in rocky areas and walls, on wooded slopes and ravines, and at the edges of woods, streams and roads.

Habitat

''Dryopteris marginalis'' has a wide distribution in the northeastern USA. It was found for the first time in Minnesota in 1981, and likely was part of the native flora for a long time but overlooked because of its rarity and its close resemblance to related species. It is listed as a threatened species in Minnesota, not so much because the species is currently threatened, but because there is only one population found on an east-facing bluff composed of sandstone that is capped with limestone. In other parts of its range it is found in woods, on talus-slopes, in rocky areas and walls, on wooded slopes and ravines, and at the edges of woods, streams and roads.