OregonFlora: Polystichum imbricans vs. Polystichum andersonii

	Polystichum imbricans	Polystichum andersonii
	imbricate sword fern	Anderson's holly fern, Anderson's sword fern
Stems		erect.
Leaves		robust; to approximately 1 m long.
Petiole		to 25 cm, densely clothed with brownish scales which continue along the rachis.
Blades		1-pinnatepinnatifid, narrowly elliptic to lanceolate, reaching 75 × 25 cm, narrowing to apex and base; abaxial veins with numerous filiform microscales; scales sparse to nearly absent adaxially distal 33% of the adaxial rachis bearing 1 or more scaly bulbils.
Pinnae		narrowly ovate to triangular, slightly falcate; to approximately 9 cm long; borne in 1 plane and not overlapping, deeply pinnatifid in mid-region with sinuses progressively reduced distally; distal lobes in the form of a triangular tooth with an incurved apical spine; proximal pinnules oblong with terminal and lateral spines, acroscopic pinnule enlarged, sometimes free to the costa (2-pinnate) on proximal pinnae.
Sori		with sparsely ciliate indusia margins.
2n		=164.

	Polystichum imbricans	Polystichum andersonii
Distribution	[WildflowerSearch map] [BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion	[Species with one variety or subspecies in Oregon.]	Riparian and moist woods, thickets, rocky areas. 700– 1600 m. BW, Casc. ID, WA; north to AK, east to MT. Native. Polystichum andersonii differs from P. californicum in its petiole, which bears chaffy scales throughout versus scales which are sparse distally. In addition, P. andersonii is more divided at the middle of the pinna with pinnules free for most of the way to the costa versus about halfway to the costa in P. californicum.
Source	Flora of Oregon, volume 1	Flora of Oregon, volume 1, page 75 Duncan Thomas
Sibling taxa	P. andersonii, P. andersonii x Polystichum munitum, P. californicum, P. californicum x Polystichum munitum, P. kruckebergii, P. lemmonii, P. lonchitis, P. munitum, P. scopulinum	P. andersonii x Polystichum munitum, P. californicum, P. californicum x Polystichum munitum, P. imbricans, P. kruckebergii, P. lemmonii, P. lonchitis, P. munitum, P. scopulinum
Subordinate taxa	P. imbricans ssp. imbricans
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, OR, WA Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Polystichum andersonii

imbricate sword fern

Anderson's holly fern, Anderson's sword fern

Stems

erect.

Leaves

robust; to approximately 1 m long.

Petiole

to 25 cm, densely clothed with brownish scales which continue along the rachis.

Blades

1-pinnatepinnatifid, narrowly elliptic to lanceolate, reaching 75 × 25 cm, narrowing to apex and base; abaxial veins with numerous filiform microscales;

scales sparse to nearly absent adaxially distal 33% of the adaxial rachis bearing 1 or more scaly bulbils.

Pinnae

narrowly ovate to triangular, slightly falcate; to approximately 9 cm long; borne in 1 plane and not overlapping, deeply pinnatifid in mid-region with sinuses progressively reduced distally;

distal lobes in the form of a triangular tooth with an incurved apical spine;

proximal pinnules oblong with terminal and lateral spines, acroscopic pinnule enlarged, sometimes free to the costa (2-pinnate) on proximal pinnae.

Sori

with sparsely ciliate indusia margins.

=164.

Polystichum andersonii

Distribution

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

[Species with one variety or subspecies in Oregon.]

Riparian and moist woods, thickets, rocky areas. 700– 1600 m. BW, Casc. ID, WA; north to AK, east to MT. Native.

Polystichum andersonii differs from P. californicum in its petiole, which bears chaffy scales throughout versus scales which are sparse distally. In addition, P. andersonii is more divided at the middle of the pinna with pinnules free for most of the way to the costa versus about halfway to the costa in P. californicum.

Source

Flora of Oregon, volume 1

Flora of Oregon, volume 1, page 75
Duncan Thomas

Sibling taxa