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Gymnocarpium robertianum

(Limestone Oak Fern)

Interesting Facts

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Common Names

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Click on the language to view common names.

Common Names in English:

Limestone Oak Fern, Scented Oak Fern, Scented Oakfern

Common Names in French:

Gymnocarpe De Robert

Common Names in unspecified:

Scented Oakfern

Description

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Genus Gymnocarpium

Plants terrestrial . Stems long-creeping, stolons absent. Leaves monomorphic , dying back in winter. Petiole ca. 1.5--3 times length of blade , base not swollen; vascular bundles 2, lateral , ± oblong in cross section . Blade broadly deltate, ternate , or ovate , 2--3-pinnate-pinnatifid, reduced distally to pinnatifid apex, herbaceous. Pinnae 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. Veins free , simple or forked . Sori in 1 row between midrib and margin, ± round ; indusia absent. Spores brownish, rugose . x = 40.

Species 8: north temperate regions , North America, Eurasia .[1]

Physical Description

Species Gymnocarpium robertianum

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. [source]

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. [source]

Size/Age/Growth

Size: under 6" tall.

Habitat

Calcareous substrates; limestone pavement, outcrops, and cliffs ; Thuja swamps ; 0--1000 m [2].

Typically found at an altitude of 0 to 2,500 meters (0 to 8,202 feet).[3]

Biology

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Growth

Sunlight: Sun Exposure: Light Shade.

Temperature: Cold Hardiness: 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b. (map)

Taxonomy

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Synonyms

Deutschl. Fl. 2: Add. Et Emend. 10. 1795 • Dryopteris robertiana (Hoffmann) C. Christensen • Gymnocarpium dryopteris var. pumilum (Dc.) Boivin • Phegopteris robertiana (Hoffmann) A. Braun Ex Aschers. • Phegopteris robertianum< /i> (Hoffmann) F&atilde • Polypodium robertianum Hoffmann • Thelypteris robertiana (Hoffmann) Slosson

Notes

Name Status: Accepted Name .

Last scrutiny: 15-Mar-2000

Similar Species

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Members of the genus Gymnocarpium

ZipcodeZoo has pages for 13 species, subspecies, varieties, forms, and cultivars in this genus:

G. achriosporum (Oakfern) · G. appalachianum (Appalachian Oak Fern) · G. disjunctum (Pacific Oak Fern) · G. dryopteris (Northern Oak Fern) · G. heterosporum (Blackspore Oakfern) · G. intermedium (Intermediate Oakfern) · G. jessoense (Asian Oakfern) · G. jessoense parvulum (Asian Oakfern) · G. jessoense subsp. parvulum (Asian Oakfern) · G. robertianum (Limestone Oak Fern) · G. × achriosporum (Oakfern) · G. x heterosporum (Black-Spore Oak Fern) · G. × intermedium (Intermediate Oakfern)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal February 01, 2008:

Identifiers

Footnotes

  1. Kathleen M. Pryer "Gymnocarpium". in Flora of North America Vol. 2. Oxford University Press. Online at EFloras.org. [back]
  2. "Gymnocarpium robertianum". in Flora of North America Vol. 2. Oxford University Press. Online at EFloras.org. [back]
  3. Mean = 333.390 meters (1,093.799 feet), Standard Deviation = 310.460 based on 1,550 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
Last Revised: 7/15/2012