Gymnocarpium appalachianum |
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Appalachian oak fern |
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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 |
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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 |
MD; NC; OH; PA; VA; WV |
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 | |
Sibling taxa | |
Name authority | Pryer & Haufler: Syst. Bot. 18: 161. (1993) |
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