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imbricate sword-fern, narrow-leaf sword fern, rock sword-fern

holly fern, mountain fern, northern holly fern, polystic faux-lonchitis

Stems

ascending to erect.

erect to occasionally ascending.

Leaves

erect to arching back at tip, 2–8 dm;

bulblets absent.

erect, not arching except at tip, 1–6 dm;

bulblets absent.

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.

1/10–1/6 of blade, densely scaly;

scales light brown, gradually diminishing in size distally.

Blade

linear-lanceolate to linear, 1-pinnate, base not or slightly narrowed.

linear, often widest above middle, 1-pinnate, base narrowed.

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.

oblong to lanceolate to falcate, proximal pinnae ± deltate, rarely overlapping, in 1 plane, 0.5–3 cm, base truncate to oblique, acroscopic auricle well developed;

margins serrulate-spiny with teeth spreading;

apex acute, subapical tooth hardly smaller than apical tooth;

microscales dense, on abaxial surface only.

Indusia

entire to sharply dentate.

entire or minutely dentate-erose.

Spores

dark brown.

dark brown.

2n

= 82.

Polystichum imbricans

Polystichum lonchitis

Habitat In rock crevices or at base of boulders, mostly in boreal and subalpine coniferous forests or alpine regions
Elevation 0–3200 m (0–10500 ft)
Distribution
from FNA
CA; OR; WA; BC; only in the flora
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[BONAP county map]
from FNA
AK; AZ; CA; CO; ID; MI; MN; MT; NV; OR; UT; WA; WI; WY; AB; BC; NF; NS; ON; QC; YT; Greenland
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[BONAP county map]
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.)

The hybrid between Polystichum lonchitis and P. acrostichoides (= P. × hagenahii Cody) is discussed under P. acrostichoides. The hybrid with P. braunii (= P. × meyeri Sleep & Reichstein) is discussed under P. braunii. In the Georgian Bay area of Ontario, P. lonchitis hybridizes with Dryopteris goldieana to produce the peculiar × Dryostichum singulare W. H. Wagner (W. H. Wagner Jr., F. S. Wagner et al. 1992).

The spiny spores of P. lonchitis are distinctive and distinguish this from dwarfed forms of other 1-pinnate species.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Pinnae oblong, less than 5 times longer than wide, adaxial surfaces facing upward and twisted out of plane of blade; leaves stiffly erect to tip; at base of boulders or in cliff crevices in exposed sites; California to British Columbia.
subsp. imbricans
1. Pinnae narrowly lanceolate, more than 5 times longer than wide, generally in 1 plane; leaf tips arching back; on forest floor in shade; only in California.
subsp. curtum
Source FNA vol. 2. FNA vol. 2.
Parent taxa Dryopteridaceae > Polystichum Dryopteridaceae > Polystichum
Sibling taxa
P. acrostichoides, P. aleuticum, P. andersonii, P. braunii, P. californicum, P. dudleyi, P. kruckebergii, P. kwakiutlii, P. lemmonii, P. lonchitis, P. microchlamys, P. munitum, P. scopulinum, P. setigerum
P. acrostichoides, P. aleuticum, P. andersonii, P. braunii, P. californicum, P. dudleyi, P. imbricans, P. kruckebergii, P. kwakiutlii, P. lemmonii, P. microchlamys, P. munitum, P. scopulinum, P. setigerum
Subordinate taxa
P. imbricans subsp. curtum, P. imbricans subsp. imbricans
Synonyms Aspidium munitum var. imbricans, P. munitum subsp. imbricans, P. munitum var. imbricans Polypodium lonchitis
Name authority (D. C. Eaton) D. H. Wagner: Pteridologia 1: 50. (1979) (Linnaeus) Roth: Tent. Fl. Germ. 3(1): 71. (1799)
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