Flora of North America species comparison

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Dryopteris celsa

Dryopteris expansa

log fern

alpine buckler fern, dryoptère dressée, northern fern, northern wood fern, spiny wood fern, spreading wood fern
Leaves

monomorphic, dying back in winter, 65–120 × 15–30 cm.

monomorphic, tardily dying back in winter, to 90 × 30 cm.
Petiole

1/3 length of leaf, scaly at least at base;

scales scattered, dark brown or tan with dark central stripe.

1/3 length of leaf, scaly at least at base;

scales scattered, brown with dark brown stripe.
Blade

green, ovate-lanceolate, gradually tapering to tip, pinnate-pinnatifid, herbaceous, not glandular.

green, deltate-ovate, 3-pinnate-pinnatifid, herbaceous, usually not glandular, occasionally finely and densely glandular.
Pinnae

± in plane of blade, lanceolate-ovate;

basal pinnae linear-oblong, much reduced, basal pinnules longer than adjacent pinnules, basal basiscopic pinnule and basal acroscopic pinnule equal;

pinnule margins crenately toothed.

± in plane of blade, lanceolate-oblong;

basal pinnae deltate, slightly reduced, basal pinnules equal to or longer than adjacent pinnules, basal basiscopic pinnule longer than basal acroscopic pinnule;

pinnule margins serrate.
Indusia

lacking glands.

lacking glands or sparsely glandular.
Sori

midway between midvein and margin of segments.

midway between midvein and margin of segments.
2n

= 164.

= 82.

Dryopteris celsa

Dryopteris expansa
Habitat Seepage slopes, hammocks and logs in swamps, mostly on the Piedmont and Coastal Plain Cool moist woods and rocky slopes
Elevation 50–800 m (200–2600 ft) 50–1500 m (200–4900 ft)
Distribution
from FNA
AL; AR; DE; GA; IL; KY; LA; MD; MI; MO; NC; NJ; NY; PA; SC; TN; VA; WV
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CA; ID; MI; MN; MT; OR; WA; WI; WY; AB; BC; NF; NT; ON; QC; YT; Greenland; Europe
[WildflowerSearch map]
[BONAP county map]
Discussion

Dryopteris celsa is a fertile allotetraploid derived from hybridization between D. goldieana and D. ludoviciana. Dryopteris celsa hybridizes with six species; hybrids can usually be identified by the dark-striped scales.

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

Dryopteris expansa is diploid and is one of the parents of D. campyloptera. Where their ranges overlap in eastern Canada, these two species are very difficult to distinguish except by chromosome number. The growth habit (D. expansa leaves are more erect) is useful in the field. Three hybrids involving D. expansa are known; all are very rare.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 2. FNA vol. 2.
Parent taxa Dryopteridaceae > Dryopteris Dryopteridaceae > Dryopteris
Sibling taxa
D. arguta, D. campyloptera, D. carthusiana, D. cinnamomea, D. clintoniana, D. cristata, D. expansa, D. filix-mas, D. fragrans, D. goldieana, D. intermedia, D. ludoviciana, D. marginalis
D. arguta, D. campyloptera, D. carthusiana, D. celsa, D. cinnamomea, D. clintoniana, D. cristata, D. filix-mas, D. fragrans, D. goldieana, D. intermedia, D. ludoviciana, D. marginalis
Synonyms D. goldiana subsp. celsa Nephrodium expansum, D. assimilis, D. dilatata subsp. americana
Name authority (W. Palmer) Knowlton: W. Palmer, & Pollard, Proc. Biol. Soc. Wash. 13: 202. (1900) (C. Presl) Fraser Jenkins & Jermy: Brit. Fern Gaz. 11: 338. (1977)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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