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D. dilatata resources
<i>Den virtuella floran</i>, close-up photosDen virtuella floran, close-up photos
photos of spines, crimping, scalesphotos of spines, crimping, scales
Hoshizaki and WilsonHoshizaki and Wilson
inoperativeBioimages: fertile pinnae (link inoperative)
fertile pinnae (D. expansa?)fertile pinnae (D. expansa?)

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Dryopteris dilatata (Hoffm.) A. Gray

Broad buckler fern

Etymology Latin: Dilatata means spread out.
Description Rhizome: erect, branching.
Frond: 100 cm high by 25 cm wide, deciduous, monomorphic, blade/stipe ratio: 3:1.
Stipe: grooved, scales ovate-lanceolate, dark brown with a darker central stripe, vascular bundles: 3-7 in a c-shaped pattern.
Blade: 3-pinnate, ovate to lanceolate, herbaceous to somewhat leathery, linear to ovate scales below, absent above.
Pinnae: 12 to 15 pair, opposite; pinnules nearest pinnule of the lowest pinnae longer than the next one; costae grooved above, continuous from rachis to costae; margins serrate, spinulose, bending under; veins free, forked.
Sori: round, in 1 row between midrib and margin, indusium: reniform, attached at a sinus, sporangia: brown then black, maturity: midsummer to mid fall.
Culture Habitat: acidic woodland. Distribution: central and northern Europe, across northern Asia. Hardy to -30°C, USDA Zone 4.
Dryopteris austriaca (Jacq.) Schinz. & Thell., misapplied
Polypodium dilatatum Hoffmann
Aspidium dilatatum Sm.
Dryopteris spinulosa ssp. dilatata (Hoffm.) C. Chr.
Lastrea dilatata Presl
Nephrodium dilatatum Desv.
Polystichum dilatatum (Hoffm.) Schumacher
Thelypteris dilatata House
Dryopteris dilatata
Dryopteris dilatata. entire frond; lower left: pinnule, margins folding under, scales on costule; center: sorus; right: stipe scale with darker center.  Illustration from Scandinavian Ferns by Benjamin Ĝllgaard and Kirsten Tind, Rhodos, 1993.
Compare to D. aemula and D. dilatata are sometimes confused, particularly with younger plants. However, mature plants of the former are 3-pinnate-pinnatifid at the base vs. just 3-pinnate for the latter. The former has segments with upturned margins; the latter has downturned margins.
Parents D. expansa and a species not in cultivation, D. azorica. Differs from the former in being 3-pinnate at the base rather than 3-pinnate-pinnatifid. It also has darker scales and the margins tend to curve under.
Dryopteris dilatata
Dryopteris dilatata.  Illustration from The Cultivated Species of the Fern Genus Dryopteris in the United States, Barbara Joe Hoshizaki and Kenneth A. Wilson, American Fern Journal, 89, 1, (1999), with permission.
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