Flora of North America species comparison

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Dryopteris intermedia

dryoptère spinuleuse, evergreen wood fern, fancy fern, intermediate woodfern
Leaves

monomorphic, green through winter, 32–90 × 10–20 cm.
Petiole

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

scales scattered, tan.
Blade

green, ovate, 3-pinnate-pinnatifid, herbaceous, glandular.
Pinnae

± in plane of blade, lanceolate-oblong;

basal pinnae lanceolate, not reduced, basal pinnules longer than adjacent pinnules, basal basiscopic pinnule longer than basal acroscopic pinnule;

pinnule margins serrate, teeth spiny.
Indusia

with minute glandular hairs.
Sori

midway between midvein and margin of segments.
2n

= 82.

Dryopteris intermedia
Habitat Moist rocky woods, especially hemlock hardwoods, ravines, and edges of swamps
Elevation 0–2000 m (0–6600 ft)
Distribution
from FNA
AL; CT; DE; GA; IA; IL; IN; KY; MA; MD; ME; MI; MN; MO; NC; NH; NJ; NY; OH; PA; RI; TN; VA; VT; WI; WV; NB; NF; NS; ON; PE; QC
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Discussion

A related taxon, Dryopteris intermedia subsp. maderensis (J. Milde ex Alston) Fraser-Jenkins, occurs on eastern Atlantic islands.

Dryopteris intermedia and the other taxa in the " D. spinulosa complex" have long confounded taxonomists. Dryopteris intermedia is diploid and is one of the parents of the allotetraploids D. carthusiana and D. campyloptera. Dryopteris intermedia hybridizes with eight species. All hybrids are easily detected by the distinctive glandular hairs on the indusia and, usually, on the costae and costules.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 2.
Parent taxa Dryopteridaceae > Dryopteris
Sibling taxa
D. arguta, D. campyloptera, D. carthusiana, D. celsa, D. cinnamomea, D. clintoniana, D. cristata, D. expansa, D. filix-mas, D. fragrans, D. goldieana, D. ludoviciana, D. marginalis
Synonyms Aspidium intermedium, D. austriaca var. intermedia, D. spinulosa var. intermedia
Name authority (Muhlenberg ex Willdenow) A. Gray: Manual 630. (1848)
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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