Etymology
Stewartii is named for John Stuart, Earl of Bute (1713-1792)
Description
Rhizome: erect, branching.
Frond: 100 cm high by 35 cm wide, deciduous, monomorphic, blade/stipe ratio: 2:1 to 3:1.
Stipe: grooved, scales dark brown, vascular bundles: 3-7 in a c-shaped pattern.
Blade: 2-pinnate, lanceolate, herbaceous to somewhat leathery, linear to ovate scales below, absent above.
Pinnae: 20 to 22 pair, subopposite, lowest pinnae anadromic; pinnules slightly pinnatifid at the base, the first lower pinnule of the lowest pinnae slightly longer than the upper pinnule, basal pinnules stalked; costae grooved above, continuous from rachis to costae; margins spiny; veins free, forked.
Sori: round, 1-2 mm, medial, on both sides of the costule, indusium: reniform, tan, at a sinus, sporangia: brown to black, maturity: late spring to summer.
Culture
Habitat: in forests at mid to high elevations.
Distribution: Himalayas: Afghanistan, Pakistan, India, Nepal.
Hardy to -20°C, USDA Zone 6.
Synonyms
Dryopteris odontoloma f. brevifolia Mehra & Khullar
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Dryopteris stewartii.
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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