Flora of North America species comparison

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Polystichum microchlamys

Polystichum aleuticum

attu hollyfern

Aleutian holly fern
Stems

erect.

erect.
Leaves

arching, 3–8 dm;

bulblets absent.

monomorphic, erect, 1–1.5 dm;

bulblets absent.
Petiole

1/8–1/4 length of leaf, densely scaly;

scales brown, diminishing in size distally.

1/6–1/4 length of leaf;

scales tan, sparse or falling off early.
Blade

broadly lanceolate, 1-pinnate-pinnatifid, base slightly narrowed.

linear-lanceolate, 1-pinnate, gradually tapered to base.
Pinnae

narrowly lanceolate, not overlapping, in 1 plane, 3–13 cm;

base oblique, proximal acroscopic segments enlarged;

margins incised to costa but segments sessile and adnate to costa for at least 2 mm, segments excised and decurrent, serrulate-spiny with teeth spreading to ascending;

apex acute with subapical and apical teeth same size;

microscales filiform, dense abaxially, sparse adaxially.

± deltate to ovate, slightly overlapping, in 1 plane, 4–8 mm;

base truncate, acroscopic auricle well developed;

margins denticulate, not spiny;

apex rounded, not dentate;

microscales linear, lacking projections, dense on both surfaces.
Indusia

erose-dentate.

entire to minutely erose-dentate.
Spore(s)

color unknown.

brown.

Polystichum microchlamys

Polystichum aleuticum
Habitat Terrestrial Growing in crevices of rocks
Elevation 0–100 m (0–300 ft) 0–400 m (0–1300 ft)
Distribution
from FNA
AK; Asia in Kamtchatka and Japan
[BONAP county map]
from FNA
AK
[BONAP county map]
Discussion

Polystichum microchlamys is found in the flora only on Attu, at the western tip of the Aleutian Archipelago.

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

Polystichum aleuticum is known only from Atka and Adak islands, Alaska. Its nearest relatives are in southwest China. Polystichum aleuticum resembles the dwarfed plants of P. kruckebergii, but it differs, especially, in its smaller, more rounded pinna apices and more abundant scales.

Of conservation concern.

(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. munitum, P. scopulinum, P. setigerum
P. acrostichoides, P. andersonii, P. braunii, P. californicum, P. dudleyi, P. imbricans, P. kruckebergii, P. kwakiutlii, P. lemmonii, P. lonchitis, P. microchlamys, P. munitum, P. scopulinum, P. setigerum
Synonyms Aspidium microchlamys
Name authority (H. Christ) Matsumura: Index Pl. Jap. 1: 343. (1904) C. Christensen: in Hultén, Svensk Bot. Tidskr. 30: 515, fig. 1a. (1936)
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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