Polystichum imbricans |
Polystichum imbricans subsp. imbricans |
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imbricate sword-fern, narrow-leaf sword fern, rock sword-fern |
imbricate fern, imbricate sword fern, narrow-leaf sword fern, rock sword fern |
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Stems | ascending to erect. |
decumbent to ascending. |
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Leaves | erect to arching back at tip, 2–8 dm; bulblets absent. |
stiffly erect, 2.5–5 dm. |
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Petiole | 1/4–1/3 length of leaf; scales abruptly diminishing in size distally and falling off early but retaining conspicuous tuft of brown scales at base. |
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Blade | linear-lanceolate to linear, 1-pinnate, base not or slightly narrowed. |
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Pinnae | oblong, slenderly lanceolate, or falcate, usually overlapping, in 1 plane or twisted out of plane of blade, 2–4 cm; base oblique, auricles well developed; margins serrulate-spiny with teeth ascending; apex cuspidate or apiculate with subapical teeth smaller than apical tooth; microscales lanceolate to linear with straight or sharply angular projections, sparse, on abaxial surface only. |
lanceolate-oblong, less than 5 times longer than wide, twisted out of plane of blade (adaxial surfaces facing upward like Venetian blinds), base usually cupped, apex cuspidate. |
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Indusia | entire to sharply dentate. |
entire. |
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Spores | dark brown. |
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Polystichum imbricans |
Polystichum imbricans subsp. imbricans |
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Habitat | Rooted at base of boulders or in cliff crevices in drier sites of mesic montane forests | |||||
Elevation | 0–2500 m (0–8200 ft) | |||||
Distribution |
CA; OR; WA; BC; only in the flora
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CA; OR; WA; BC |
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Discussion | Polystichum imbricans is one of the postulated ancestors of two allopolyploids, P. californicum and P. scopulinum (D. H. Wagner 1979). Relationships to P. munitum are discussed under that species. Subspecies 2. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Polystichum imbricans subsp. imbricans grows in the Coast Ranges and the Sierra-Cascade axis. It is isolated in the Wallowa Mountains of eastern Oregon. Sun forms of Polystichum munitum are often mistaken for P. imbricans; characteristics of the distal petiolar scales and indusial margins are more reliable than gross morphologic features for distinguishing them. Polystichum imbricans has narrow distal petiolar scales that fall off early; P. munitum has wide distal petiolar scales (the largest more than 1 mm wide) that are persistent. Polystichum imbricans hybridizes readily with P. munitum, the hybrids usually being sterile but in some places forming hybrid swarms because of partial fertility of the hybrids (D. H. Wagner 1979). The hybrids with P. californicum are discussed under that species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 2. | FNA vol. 2. | ||||
Parent taxa | Dryopteridaceae > Polystichum | Dryopteridaceae > Polystichum > Polystichum imbricans | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Aspidium munitum var. imbricans, P. munitum subsp. imbricans, P. munitum var. imbricans | P. munitum subsp. nudatum | ||||
Name authority | (D. C. Eaton) D. H. Wagner: Pteridologia 1: 50. (1979) | (D. C. Eaton) D. H. Wagner | ||||
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