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P. scopulinum resources
Distribution
North AmericaNorth America
Drawing
Britton & BrownBritton & Brown
inoperativeVascular Plants of the Pacific Northwest (pdf) (link inoperative)
Flora
Flora of North AmericaFlora of North America
Jepson ManualJepson Manual
Photo
habit, on serpentinehabit, on serpentine

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     lepidocaulon  lonchitis
     makinoi  munitum
     neolobatum  polyblepharum
     proliferum  retroso-paleaceum
     rigens  scopulinum
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     tagawanum  tripteron
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    Woodwardia
 
Polystichum scopulinum (D. C. Eaton) Maxon

Mountain holly fern, rock sword fern

Etymology Scopulinum means of the rocks. See section marked Culture.
Description Rhizome: erect, short, stout, scaly.
Frond: 40 cm high by 6 cm wide, evergreen, monomorphic, blade/stipe ratio: 2:1 to 4:1.
Stipe: grooved, densely scaly but scales falling off above, light brown, abruptly diminishing in size upward, vascular bundles: 4 or more, in an arc.
Blade: 1-pinnate-pinnatifid, but described also as merely 1-pinnate or in older specimen 2-pinnate, lanceolate, base narrowed, glossy, microscales narrowly lanceolate, sparse, on lower surface only, and falling soon.
Pinnae: 20 to 40 pair, oblong-lanceolate, 1--3 cm, basal lobes (the upper one larger, eared outward) cut to the costa, the remainder of the pinna more accurately described as serrate, anadromic; margins serrate, spiny, 8-25 spines on each edge of the pinna; veins free, forked.
Sori: round, touching at maturity, nearly covering the entire surface on the upper two-thirds of the frond, except for the basal lobes, in 1 row on both sides of the costa, indusium: peltate, central, sporangia: brown, maturity: late spring.
Dimensionality: pinnae folded inward and twisted horizontally.
Culture Habitat: rock crevices and at base of boulders, serpentine to acidic substrates, usually exposed to full sun . Distribution: British Columbia to Arizona, disjunct in Quebec, Newfoundland. Hardy to -30C, USDA Zone 4.
Synonyms
Aspidium aculeatum (Linnaeus) Swartz var. scopulinum D. C. Eaton
Polystichum mohrioides (Bory) C. Presl var. scopulinum (D. C. Eaton) Fernald
Aetopteron scopulinum House
Polystichum scopulinum
Polystichum scopulinum. Frond, pinna, sorus.  Illustration by Edgar Paulton, from How to Know the Ferns and Fern Allies, John T. Mickel, 1979 Wm. C. Brown Co.
Notes
Compare to the similar P. kruckebergii, differentiated by the pinna margins: 8 or more, often 12, teeth here vs. 6 in P. kruckebergii, and the margin is much spinier in P. kruckebergii.
Parents P. imbricans and P. lemmonii. The former is distinctly 1-pinnate and the stipe is shorter with a blade/stipe ration greater than 4:1. The latter is not spiny and is distinctly 2-pinnate.
Polystichum scopulinum
Polystichum scopulinum. a) fronds, blades widest at the middle; b) fertile pinna with about a dozen teeth.  Illustration by V. Fulford from Ferns and Fern Allies of Canada, William J. Cody and Donald M. Britton, 1989, Agriculture Canada, used with permission.
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