Gymnocarpium robertianum (Hoffm.) Newman:
Canada (North America)
Pakistan (Asia)
United States (North America)
China (Asia)

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

Global Range: Canada: the Yukon, the Northwest Territories, Newfoundland, British Columbia, Quebec, New Brunswick, and Ontario. US: Alaska, Idaho, Montana, Minnesota, Iowa, Tennessee, Maine, Pennsylvania, New York, Wisconsin and Michigan.

Gymnocarpium robertianum occurs in numerous localities in eastern Canada, especially in Ontario and Quebec where it is widely distributed; populations are small. Hybrids with G . robertianum are extremely rare. Gymnocarpium × heterosporum W. H. Wagner, a putative triploid hybrid between G . robertianum and G . appalachianum , is known only from one county in Pennsylvania (plants now extirpated, K. M. Pryer 1992). Gymnocarpium × achriosporum Sarvela, a putative tetraploid hybrid between G . robertianum and G . dryopteris , is known only from Sweden and two localities in Quebec. Both hybrids resemble G . robertianum in their leaf morphology and dense glandularity but have black, malformed spores.

Stems 1--2 mm diam.; scales 2--4 mm. Fertile leaves usually 10--52 cm. Petiole 5--33 cm, with numerous glandular hairs distally; scales 2--6 mm. Blade broadly deltate, 2--3-pinnate-pinnatifid, 5--19 cm, usually firm and robust, abaxial surface moderately to densely glandular, rachis densely glandular, adaxial surface moderately glandular. Pinna apex acute. Proximal pinnae 3--13 cm, ± perpendicular to rachis, basiscopic pinnules ± perpendicular to costa; basal basiscopic pinnules either sessile or stalked, pinnate-pinnatifid or pinnatifid, if sessile then with basal basiscopic pinnulet usually shorter than adjacent pinnulet; 2d basal basiscopic pinnule sometimes stalked, if sessile then with basal basiscopic pinnulet shorter than or equaling adjacent pinnulet; basal acroscopic pinnule sometimes stalked, if sessile then with basal basiscopic pinnulet shorter than or equaling adjacent pinnulet. Pinnae of 2d pair usually stalked, if sessile then with basal basiscopic pinnule usually shorter than adjacent pinnule and equaling basal acroscopic pinnule; basal acroscopic pinnule shorter than adjacent pinnule, apex often entire, rounded. Pinnae of 3d pair usually sessile with basal basiscopic pinnule shorter than adjacent pinnule and equaling basal acroscopic pinnule; basal acroscopic pinnule equaling or shorter than adjacent pinnule. Ultimate segments of proximal pinnae oblong, entire to slightly crenate, apex entire, rounded. Spores 34--39 µm. 2 n = 160.

Polypodium robertianum Hoffmann, Deutschl. Fl. 2: add. et emend. 10. 1795; Dryopteris robertiana (Hoffmann) C. Christensen; Phegopteris robertianum (Hoffmann) Fée; Thelypteris robertiana (Hoffmann) Slosson

Calcareous substrates; limestone pavement, outcrops, and cliffs; Thuja swamps; 0--1000 m; Man., N.B., Nfld., Ont., Que.; Iowa, Mich., Minn., Wis.; Europe; Asia in Caucasus Mountains.

Comments: Talus slope forest, calcareous ledges & shorelines. Cool n.-facing slopes (Cornus canadensis & Equisetum scirpoides)

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: Widespread.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 1
Species: 1
Species With Barcodes: 1

Canada

Rounded National Status Rank: N3 - Vulnerable

United States

Rounded National Status Rank: NNR - Unranked

Rounded Global Status Rank: G5 - Secure

Reasons: Species occurs over a broad range of Canada and the northern US. Because it occurs on habitat which is unsuitable for other needs, it is not highly threatened.