Woodsia.obtusifolia.Marielle Anzelone.Metro North wall. N.Y.C. 8/002 (Accessed 4/2017).

Woodsia obtusa is a fern to 55 cm tall (usually less than 20 cm), from a scaly rhizomes. 

Leaves in tufts, stalk very short, brittle, base orange, yellow above, somewhat glandular-hairy; white-hairy and scaly when young; blade narrow, to 10 cm wide, twice pinnate-pinnately lobed, midrib hairy, scaly, leaflets 13-18 per side, widely spaced along midrib (rachis), almost stalkless, bluntly, narrowly triangular, hairy below, fertile leaflets narrow, pointed, secondary leaflets 6-13 per side of leaflet, oblong, rounded, deeply pinnately lobed, 4-6 bluntly toothed lobes per side, fertile lobes with margins rolled under over spore cases when young. 

Woodsia obtusa.spore cases. ©2013 by Will Cook. carolinanature.com (Accessed 4/2017).

Spore cases along lobe margins. 

Wetland status: UPL. 

Woodsia obtusifolia.Marielle Anzelone.Metro North railroad wall

Frequency in NYC: Very infrequent but locally common on Park Ave. rail trestle, in mortar between stones. 

Origin: Native. 

Habitat: Shaded, rocky slopes, in circumneutral soil.

Thelypteris simulata.Janet Novak.www.ct-botanica.society.org (Accessed 3/2014)

Thelypteris simulata  is a fern from a creeping rhizome. 

Leaves arising in small clusters from rhizome tips, to 50 cm long, 15 cm wide; stalk to 35 cm, base pale brown, slightly scaly, yellow-green above; blade once pinnate-pinnately lobed, leaflets tapered at both ends, lobed almost to midrib, lobes blunt-tipped. 

Spore cases along veins, kidney-shaped (Cobb 1963). 

Wetland status: FACW+. 

Frequency in NYC: Very infrequent. 

Origin: Native. 

Thelypteris simulata.spore cases (sori).© 2003 Gary Fewless.University of Wisconsin – Green Bay.Cofrin Center for Biology.uwgb.edu  (Accessed 3/2017).

Habitat: Acid bogs and swamp forests. Apparently shade tolerant. 

Notes: Similar to T. palustris but blade of T. palustris is described as narrower, and spore cases differ.

Thelypteris palustris.Janet Novak. ct-botanical-society.org. (Accessed 6/2014).

Thelypteris palustris is a fern from a slender, creeping rhizome, colonial. 

Leaves arising singly along the rhizome; to 80 cm long, stalk to 35 cm long, on sterile leaves, to 70 cm on fertile leaves (longer than blade), black at base, smooth; blade to 40 cm long, 20 cm wide, tip tapered, base slightly narrowed, once pinnate-pinnately lobed, leaflets (pinnae) to 2 cm wide, lobed almost to leaflet midrib, lobes, to 1 cm long, 0.5 cm wide, midribs and veins hairy, margin smooth (entire); fertile lobes with margins curled inward. 

Thelypteris palustris.sporophyll. Zihao Wang.Jamaica Bay, New York City. W.L.R.9/2015 (Accessed 4/2017).

Spore cases numerous, on upper leaflets of fertile fronds near midrib, eventually back of leaflet becoming brown with ripening sori. 

Wetland status: FACW+. 

Frequency in NYC: Infrequent. 

Origin: Native to NYC. 

Habitat: Open marshes, pond edges, wet soil. Not very tolerant of shade.

Thelypteris noveboracensis.L. Mellichamp.Herbarium University of Michigan.michiganflora.net (Accessed 5/2016).

Thelypteris noveboracensis is a fern to 90 cm tall, aggressively colonial from a dark brown, slender, branching rhizome. 

Leaves deciduous, yellow-green, in small tufts from tips of rhizome branches, stalk 12-20 cm long, dark, scaly at base, slightly hairy; blade once pinnate-pinnatifid, to 15 cm wide, tapering sharply at both ends, leaf axis green, leaflets stalkless, to 1.5 cm wide, becoming much smaller near leaf base, lobed to midvein, lobes numerous, margins entire, tips rounded, midrib and veins hairy. 

Tthelypteris noveboracensis.spore cases.Transformational Gardening.transformationalgardening.com (Accessed 3/2017).

Spore cases sparse, near margins of lobes, covered by kidney-shaped, hairy structure (indusium). 

Wetland status: FAC. 

Frequency in NYC: Occasional. 

Origin: Native to NYC. 

Habitat: Moist, bright woods. 

Notes: Tolerates acid soil to pH 3.9 (Greller et al. 1990). Easily confused with hay-scented fern upon casual observation or from winter remnants (see above).

Thelypteris hexagonoptera. Michael Hough © 2004-2010. Botany Blog Plants of the Northeastern U.S. botany.thismia.com (Accessed 4/2017).

Thelypteris hexagonoptera is a fern to 80 cm tall, from a slender, creeping, branching scaly rhizome. 

Leaves deciduous, arising singly; leaf stalk hairy, somewhat scaly below, smooth above; blade twice pinnate, to 40 cm long, broadly triangular in outline, midrib winged, leaflets 10-15, to 7 cm wide, the lowest are the largest, midribs broadly winged, secondary leaflets 20 per side, tapered at both ends, irregularly, bluntly toothed or shallowly lobed. 

Spore cases scattered near leaflet margins at ends of veins. 

Wetland status: FAC. 

Frequency in NYC: Very infrequent. 

Origin: Native to NYC. 

Habitat: Moist, undisturbed woods.

Polystichum acrostichoides.growth form with sporophylls.M. B. Gargiullo. 6/2015.

Polystichum acrostichoides is a fern from a short rhizome. 

Leaves tufted, evergreen, 30-75 cm long, stalk much shorter than blade; blade 5-12 cm wide, once pinnate, leaflets alternate, 20-35 per side, upper surface leathery, dark green, lower surface pale, scaly-hairy, lobed at base on upper side only; erect when young, becoming prostrate later in season, after frost. 

Polystichum acrostichoides. spores on upper leaflets. Copyright © 2009 by D. L. Nickrent. phytoimages.siu.edu (Accessed 4/2017).

Spore cases forming a dense row along each side of midrib on narrowed leaflets at tops of fronds; June-July. 

Wetland status: FACU. 

Frequency in NYC: Occasional. 

Origin: Native to NYC. 

Habitat: Understory of moist, undisturbed forest, shade tolerant, usually on slopes where leaf litter does not accumulate, spreads very slowly. New plants produced on patches of bare soil (Gargiullo, personal observation). 

Notes: Leaves expand in April-May, before canopy closure and fern continues to photosynthesize during mild winter days, they die as new fronds expand the following spring, dead fronds persistent on rhizome (Minoletti and Boerner 1993). Apparently not eaten by anything (M. Gargiullo personal, observation).

Dryopteris intermedia. Tom Kent. Flora Finder. NH. florafinder.org (Accessed 4/2018).

Dryopteris intermedia is a fern from a short, scaly ascending to erect rhizome, roots sparingly colonized by VA mycorrhizas (Brundrett and Kendrick 1988). 

Leaves in a rosette, to 80 cm long, evergreen; stalk 10-30 cm, scales broad, pale brown with darker markings; blade to 50 cm long, 20 cm wide, tip long-tapered, base blunt, widest just above base, twice pinnate-pinnately lobed to three times pinnate, lowest leaflet with its lowest secondary leaflet shorter than the next above it; secondary leaflets deeply lobed and toothed, teeth bristle-tipped (spinulose). 

Dryopteris intermedia.Glen Mittelhauser.New England Wild Flower Society.gobotany.newenglandwild.org (Accessed 4/2018).

Spore cases midway between midrib and margin of ultimate divisions. 

Wetland status: FACU. 

Frequency in NYC: Infrequent. 

Origin: Native to NYC. 

Habitat: Moist, rich woods. Often growing on decayed wood (Brundrett and Kendrick 1988). 

Notes: New leaves emerging in spring as tree canopy closes, replacing over-wintered leaves.

Dryopteris goldiana plants. By Donald Cameron. Copyright © 2018 Donald Cameron. New England Wild Flower Society. gobotany.newenglandwild.org (Accessed 4/2018).

Dryopteris goldiana| is a fern from the end of an ascending rhizome.

Dryopteris goldiana leaf. By Donald Cameron. Copyright © 2018 Donald Cameron. New England Wild Flower Society. gobotany.newenglandwild.org (Accessed 4/2018).

Leaves semi-evergreen, to 1.2 m long, in a rosette, stalk to 40 cm, base densely scaly, scales to 2 cm long, central part dark brown with paler margin; blade to 30 cm wide, egg-shaped in outline, leathery, bronze-green, once pinnate, leaflets (pinnae) 12-16 per side, to 4.5 cm wide, these pinnately lobed almost to midrib, tip abruptly pointed, base only slightly narrowed, lowest lobes shorter than those above; lobes to 3 x 0.9 cm, toothed, teeth bristle-tipped.

Dryopteris goldiana sori. By Donald Cameron. Copyright © 2018 Donald Cameron. New England Wild Flower Society. gobotany.newenglandwild.org (Accessed 4/2018).

Spore cases small, close to midrib, kidney-shaped.

Wetland status: FAC+.

Frequency in NYC: Very infrequent.

Origin: Native to NYC.

Habitat: Moist to wet woods, in rich circumneutral soil.

Dryopteris cristata.commons.wikipedia. org (Accessed 3/2014).

Dryopteris cristata is a fern from the end of a short, creeping rhizome. 

Leaves evergreen, 35-80 cm long, in rosettes, stalk and midrib brown-scaly; blades twice pinnate and pinnately lobed, to three times pinnate, narrow; with 10-25 pinnate leaflets (pinnae) per side, leaflets 5-9 cm long, 3-4 cm wide, widest just above base, firm, bluish-green, tilted towards the horizontal plane, lower leaflets widely spaced, broadly triangular about 2.5 cm long, horizontal, upper leaflets more elongate and crowded, secondary leaflets about 6 per side, oblong, tips blunt, margins toothed; fertile blades deciduous. 

Spore cases round, midway between midvein and margin (Cobb 1963). 

Wetland status: FACW+. 

Frequency in NYC: Very infrequent. 

Origin: Native. 

Habitat: Wet to moist forest understory. 

Notes: A host of the white-spored fir rust fungi: Milesina fructuosa, M. marginalis, and Uredinopsis atkinsonii (a fir-fern rust, Basidiomycotina) (Sinclair et al. 1987). The closely related, shade tolerant, semi-evergreen fern, D. marginalis (which has not been found in NYC since before 1980) has a leaf life span of 30 weeks. It requires at least 0.2% sunlight in order to survive (compensation point), but cannot use more than 3.0% full sunlight (saturation point) (Hicks and Chabot 1985).

Dryopteris celsa.J.S. Peterson, hosted by the USDA-NRCS PLANTS Database (Accessed 12/2014).

Dryopteris celsa is a fern to 1.2 m tall, from a creeping rhizome. 

Leaves deciduous, stalk to 50 cm long, scales large, dark center, pale margin, and hair-like pale brown scales; blade 35-60 cm long, 15-30 cm wide, not scaly, egg-shaped to oblong, gradually tapered to tip, base not tapered much, pinnate, leaflets to 18 pairs, pinnately lobed, largest leaflets with 12-15 pairs lobes to 2.5 cm long, margins distantly toothed, basal leaflets narrowed below, lowest segments shorter than those adjacent. 

Dryopteris celsa, sporangia,I© George Yatskievych, 2006-2011 (Accessed 4/2018).

Spore cases midway between margin and midrib. 

Wetland status: OBL. 

Frequency in NYC: Rare; NYS S1, E. 

Origin: Mostly southern U.S. north to NJ, PA with rare disjunct populations in NYS. 

Habitat: On rotting logs or rich, moist to wet soil.