Gymnocarpium
Gymnocarpium appalachianum
oak-fern
Appalachian oak fern
long-creeping, stolons absent.
0.5–1.5 mm diam.;
scales 1.5–3 mm.
monomorphic, dying back in winter.
usually 10–32 cm.
ca. 1.5–3 times length of blade, base not swollen;
vascular bundles 2, lateral, ± oblong in cross section.
6–20 cm, with sparse glandular hairs distally;
scales 2–5 mm.
broadly deltate, ternate, or ovate, 2–3-pinnate-pinnatifid, reduced distally to pinnatifid apex, herbaceous.
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.
of proximal pinnae oblong, entire to crenate, apex entire, rounded.
weakly articulate to rachis but persistent, segment margins entire to crenate;
proximal pinnae longest, petiolulate, usually ± inequilateral with pinnules on basiscopic side longer than those on acroscopic side;
costae adaxially grooved, grooves not continuous from rachis to costae;
indument lacking or of minute (0.1 mm) glands abaxially and sometimes along costae adaxially.
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.
free, simple or forked.
in 1 row between midrib and margin, ± round;
indusia absent.
brownish, rugose.
27–31 µm. 2n = 80.
apex entire, rounded.
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.
= 40.
Gymnocarpium
Gymnocarpium appalachianum
Species 8 (5 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.)
1. Adaxial blade surface glabrous or moderately glandular, abaxial blade surface and rachis moderately or densely glandular. | → 2 |
1. Adaxial and abaxial blade surfaces and rachis essentially glabrous. | → 3 |
2. Blades glabrous on adaxial surface; proximal pinnae and basiscopic pinnules of proximal pinnae curving toward apex of leaf and apex of pinna, respectively; pinnae of 2d pair almost always sessile with basal pinnules ± equal in length to adjacent pinnules. | jessoense subsp. parvulum |
2. Blades moderately glandular on adaxial surface; proximal pinnae and basiscopic pinnules of proximal pinnae ± perpendicular to rachis and costa, respectively; pinnae of 2d pair usually stalked, or if sessile with basal pinnules shorter than adjacent pinnules. | G. robertianum |
3. Pinnae of 2d pair and basal basiscopic pinnule of proximal pinnae stalked. | G. appalachianum |
3. Pinnae of 2d pair sessile or rarely stalked; proximal basiscopic pinnule of basal pinnae sessile. | → 4 |
4. Pinnae of 2d pair sessile with basal pinnules unequal in length (basiscopic markedly longer); ultimate segments of proximal pinnae slightly lobed to crenate, apex often crenulate, acute; blades 8-24 cm. | G. disjunctum |
4. Pinnae of 2d pair rarely stalked, if sessile with basal pinnules ± equal in length (basiscopic = acroscopic); ultimate segments of proximal pinnae crenate to entire, apex entire, rounded; blades 3-14 cm. | → 5 |
5. Sessile basal basiscopic pinnule of proximal pinnae with basal basiscopic pinnulet (division of pinnule) ± equal in length to adjacent pinnulet; pinnae of 2d pair usually sessile, with basal pinnules ± equal in length to adjacent basal pinnule; spores 34-39 µm. | G. dryopteris |
5. Sessile basal basiscopic pinnule of proximal pinnae with basal basiscopic pinnulet shorter than adjacent pinnulet; pinnae of 2d pair sessile, with basal pinnules shorter than adjacent pinnule, or 2d basal pinnae rarely stalked; spores 27-31 µm. | G. appalachianum |
OR
WA
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
MD Biodiversity
