Vascular Plants of North Carolina
Account for Marsh Fern - Thelypteris palustris   SchottOnly member of Thelypteris in NC.
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Section 2 » Order Polypodiales » Family Thelypteridaceae
AuthorSchott
DistributionPresent over nearly all of the state, but mainly in the lower half of the Coastal Plain, the mountains, and the northern Piedmont. Surprisingly few records for the southern and western Piedmont, and completely absent from the Sandhills region.

This is an Eastern species, widespread from eastern Canada south to VA and IA, and less numerous southward to southern FL and central TX.
AbundanceFrequent to common in the lower Coastal Plain, but much less numerous westward. Generally uncommon across the rest of the state, and surprisingly rare in much of the southern and western Piedmont (for an "Eastern US" species).
HabitatThis is a requisite wetland species, of sunny to partly sunny places. It prefers rather rich soil of muddy spots, such as in fresh marshes, especially in tidal freshwater ones, openings in bottomlands, wet thickets, and bogs.
See also Habitat Account for General Broadleaf Herbaceous Mires
PhenologyFruits from June to September.
IdentificationThis is a rather fragile species, growing in very dense stands with stipes closely spaced. The stipe is yellow-green, about 8-10 inches long, and the blade is about as long, with a lanceolate to oblong shape, and averaging about 4 inches wide. The blade is cut pinnate-pinnatifid, with the pinnules oblong to somewhat triangular and the incisions not quite cut to the midrib of the pinnae. There are about 15-20 pairs of pinnae, variously opposite to alternate, with the upper ones much shorter than lower ones, yielding a tapering tip to the blade. Sori are rounded and densely packed on the undersides of the fertile fronds. (Sterile fronds are similar but shorter and, of course, have no sori.) The fertile fronds often have the margins of the pinnules rolled under somewhat, as if to partly hide the sori. New York Fern (Parathelypteris noveboracensis) also grows in dense stands and is similarly rather fragile, but it grows mostly in forests, and its blades are tapering to the base; Marsh Fern blades have the lower pinnae essentially the same length as several above them. The very rare montane Bog Fern (Coryphopteris simulata) is notoriously similar to Marsh Fern, despite being moved to a different genus; they can perhaps grow in the same bogs. It can be separated mainly with a hand lens. Bog Fern has "Lateral veinlets of pinna lobes unbranched, or rarely forked; abaxial [lower] surface of blade with scattered silvery to golden resinous glands" (Wofford 1989); Marsh Fern has "Lateral veinlets of pinna lobes mostly forked; abaxial [lower] surface of the blade without glands" (Wofford 1989).
Taxonomic CommentsThis species has several varieties, with the one in NC being var. pubescens.

Other Common Name(s)Eastern Marsh Fern, Northern Marsh Fern
State RankS5
Global RankG5
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