Flora of North America species comparison

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Polystichum scopulinum

Polystichum setigerum

Eaton's holly fern, mountain holly fern, polystic des rochers, rock sword fern

Alaska holly fern, Alaska sword fern
Stems

ascending.

erect.
Leaves

erect, 1–3(–5) dm;

bulblets absent.

arching, 4–10 dm;

bulblets absent.
Petiole

1/5–1/3 length of leaf, densely scaly but scales falling off distally;

scales light brown, abruptly diminishing in size distally.

1/8–1/5 length of leaf, densely scaly;

scales light brown, gradually diminishing in size distally.
Blade

narrowly lanceolate, 1-pinnate-pinnatifid, base narrowed.

lanceolate, deeply 1-pinnate-pinnatifid to 2-pinnate, base narrowed.
Pinnae

oblong-lanceolate, overlapping, folded inward and twisted horizontally, 1–3 cm;

base oblique;

margins serrulate with teeth curved inward;

apex obtuse to cuspidate with subapical teeth smaller than apical tooth;

microscales narrowly lanceolate, with stout projections, sparse, on abaxial surface only.

lanceolate, not overlapping, in 1 plane, 4–8 cm, base oblique, margins incised to costa on middle pinnae, serrulate-spiny with teeth spreading-ascending, apex acute-apiculate with subapical and apical teeth same size;

microscales filiform, sparse abaxially, confined to costa adaxially.
Indusia

entire-ciliate.

erose-ciliate.
Spores

brown.

brown.
2n

= 164.

= 246.

Polystichum scopulinum

Polystichum setigerum
Habitat Rock crevices and at base of boulders, serpentine to acidic substrates, usually exposed to full sun Forest floor in lowland coastal forests
Elevation 0–3500 m (0–11500 ft) 0–250 m (0–800 ft)
Distribution
from FNA
AZ; CA; CO; ID; MT; NV; OR; UT; WA; WY; BC; NF; QC
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; BC
[BONAP county map]
Discussion

Polystichum scopulinum is widely distributed in the United States west of the 110th meridian, where it occurs in sporadic, usually small populations. The species is abundant only on montane serpentine outcrops. The populations in Newfoundland and Quebec are dramatically disjunct.

Polystichum scopulinum is an allopolyploid, believed on morphologic grounds to be derived from P. imbricans × lemmonii (D. H. Wagner 1979). Based on putative hybridization between P. scopulinum and P. munitum (P. S. Soltis et al. 1989; W. H. Wagner Jr. 1973), however, P. munitum may also be involved. This hybrid is discussed under P. californicum.

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

Polystichum setigerum is disjunct on Attu Island at the western tip of the Aleutian Archipelago. It is presumed to be of hybrid origin, the result of a cross between P. munitum and P. braunii (D. H. Wagner 1979). This hybrid has been produced experimentally (A. Sleep and T. Reichstein 1967) and is reported from British Columbia (see discussion under P. braunii).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
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. imbricans, P. kruckebergii, P. kwakiutlii, P. lemmonii, P. lonchitis, P. microchlamys, P. munitum, P. setigerum
P. acrostichoides, P. aleuticum, P. andersonii, P. braunii, P. californicum, P. dudleyi, P. imbricans, P. kruckebergii, P. kwakiutlii, P. lemmonii, P. lonchitis, P. microchlamys, P. munitum, P. scopulinum
Synonyms Aspidium aculeatum var. scopulinum, P. mohrioides var. scopulinum Nephrodium setigerum, P. braunii subsp. alaskense, P. braunii var. alaskense
Name authority (D. C. Eaton) Maxon: Fern Bull. 8: 29. (1900) (C. Presl) C. Presl: Tent. Pterid. 83. (1836)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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