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Appalachian oak fern

Stems

0.5–1.5 mm diam.;

scales 1.5–3 mm.

Fertile leaves

usually 10–32 cm.

Petiole

6–20 cm, with sparse glandular hairs distally;

scales 2–5 mm.

Blade

broadly deltate, 2–3-pinnate-pinnatifid, 4–12 cm, lax and delicate, abaxial surface and rachis glabrous or with occasional glandular hairs, adaxial surface glabrous.

Ultimate segments

of proximal pinnae oblong, entire to crenate, apex entire, rounded.

Pinnae

of 2d pair usually stalked, if sessile then with basal basiscopic pinnule shorter than adjacent pinnule and equaling basal acroscopic pinnule;

basal acroscopic pinnule shorter than adjacent pinnule, often with entire, rounded apex.;

pinnae of 3d pair usually sessile with basal basiscopic pinnule shorter than adjacent pinnule and equaling or shorter than basal acroscopic pinnule;

basal acroscopic pinnule equaling or shorter than adjacent pinnule.

Spores

27–31 µm. 2n = 80.

Pinna

apex entire, rounded.

Proximal

pinnae 3–10 cm, ± perpendicular to rachis, with basiscopic pinnules ± perpendicular to costa;

basal basiscopic pinnules stalked or sessile, pinnate-pinnatifid or pinnatifid, if sessile then with basal basiscopic pinnulet (division of pinnule) always shorter than adjacent pinnulet; 2d basal basiscopic pinnule infrequently stalked, if sessile then with basal basiscopic pinnulet shorter than adjacent pinnulet;

basal acroscopic pinnule occasionally stalked, if sessile then with basal basiscopic pinnulet shorter than adjacent pinnulet.

Gymnocarpium appalachianum

Habitat Maple-birch-hemlock (Acer - Betula - Tsuga) woods on mountain slopes and summits, on moist sandstone or talus slopes with cold air seepage (algific)
Elevation 200–1400 m (700–4600 ft)
Distribution
from FNA
MD; NC; OH; PA; VA; WV
[BONAP county map]
Discussion

Gymnocarpium appalachianum, restricted to the Appalachian region, is a very local endemic.

Of conservation concern.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 2.
Parent taxa Dryopteridaceae > Gymnocarpium
Sibling taxa
G. disjunctum, G. dryopteris, G. jessoense, G. robertianum
Name authority Pryer & Haufler: Syst. Bot. 18: 161. (1993)
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