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D. crassirhizoma resources
Flora of JapanFlora of Japan
Hoshizaki and WilsonHoshizaki and Wilson
inoperativefour diagnostic close-ups (link inoperative)
standard view of habitstandard view of habit
two amazing shotstwo amazing shots
Photo index
PlantSystematics.org, diagnostic photosPlantSystematics.org, diagnostic photos

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Dryopteris crassirhizoma Nakai
Etymology From the Latin Crassus, thick + the Greek rhizoma, mass of roots. But remember that a rhizome is an underground stem.
Description Rhizome: stout, 10 cm across, erect, bearing more than ten ascending fronds in a beautiful whorl, scales lanceolate to linear, larger ones more than 4 cm long.
Frond: 100 cm high by 20 cm wide, deciduous, monomorphic, blade/stipe ratio: 4:1.
Stipe: grooved, straw colored, densly scaly, lanceolate to linear, brown, lustrous, vascular bundles: 3-7 in a c-shaped pattern.
Blade: almost 2-pinnate, deltate-ovate to lanceolate, widest at the middle, herbaceous , linear to ovate scales below, absent above.
Pinnae: catadromous; costae grooved above, continuous from rachis to costae; segments oblong, rounded; margins crenate; veins free, forked, immersed on upper surface.
Sori: round, confined to upper pinnae, indusium: reniform, at a sinus, sporangia: brownish.
Culture Habitat: wooded slopes. Distribution: Japan, Korea, Manchuria, ne Asia. Hardy to -25C, USDA Zone 5.
Dryopteris filix-mas (L.) Schott, misapplied
Dryopteris buschiana Fomin
Dryopteris setosa Kudo
Dryopteris crassirhizoma
Dryopteris crassirhizoma. Perfectly symmetrical crown.  Photo: Tom Stuart
Persistence Another report: evergreen (Mickel, Ferns for American Gardens)
Dryopteris crassirhizoma
Dryopteris crassirhizoma. Fertile pinna: more detail on the click-through.  Photo: Tom Stuart
Dryopteris crassirhizoma
Dryopteris crassirhizoma.  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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