[Ferns East of the Crest of the Cascade Mountains of Oregon and Washington] [Swordferns East of the Crest of the Cascade Mountains of Oregon and Washington]

Narrow-leaved Sword-fern, Imbricate Sword Fern

Polystichum imbricans ssp. imbricans

Synonym: Polystichum munitum var. imbricans

Narrow-leaved Sword-fern, Imbricate Sword Fern: Polystichum imbricans ssp. imbricans (Synonym: Polystichum munitum var. imbricans)

The photo above shows a cluster of the fronds of imbricate sword fern arising from a rock face along forest road #2360 just north of its intersection with road #071 on the southwestern slopes of Mt. Adams.............October 14, 2005. Note the numerous persistent, dried fronds at the base of the plant.

Ventral surface and sori of the leaflets of Narrow-leaved Sword-fern, Imbricate Sword Fern: Polystichum imbricans ssp. imbricans (Synonym: Polystichum munitum var. imbricans)

The photo above shows several different leaflets of imbricate sword fern. The lower leaflet shows a dorsal view, while the two upper leaflets show ventral views with their spore cases. Note the spreading to spreading-ascending spines along the margin of the lowermost leaflet. Photographed in talus just downslope of the Mt. Adams Viewpoint along Rd #23, about one-half mile south of the intersection with Rd #8810...........September 25, 2005.

Sori of Narrow-leaved Sword-fern, Imbricate Sword Fern: Polystichum imbricans ssp. imbricans (Synonym: Polystichum munitum var. imbricans)

The photo above shows a close-up of one leathery leaflet of imbricate sword fern with its closely spaced spore capsules. Note the central, light colored indusium in each spore capsule. Photographed in talus just downslope of the Mt. Adams Viewpoint along Rd #23, about one-half mile south of the intersection with Rd #8810...........September 25, 2005.

Ventral frond surface of Narrow-leaved Sword-fern, Imbricate Sword Fern: Polystichum imbricans ssp. imbricans (Synonym: Polystichum munitum var. imbricans)

The upper half of a frond of imbricate sword fern as seen in talus just downslope of the Mt. Adams Viewpoint along Rd #23, about one-half mile south of the intersection with Rd #8810...........September 25, 2005. Note the large tooth at the base of each leaflet that is not cut into the leaflet. The leaflets at the base of the frond are either the longest on the frond, or about the same size as those at mid frond.

Narrow-leaved Sword-fern, Imbricate Sword Fern: Polystichum imbricans ssp. imbricans (Synonym: Polystichum munitum var. imbricans) ----- Narrow-leaved Sword-fern, Imbricate Sword Fern: Polystichum imbricans ssp. imbricans (Synonym: Polystichum munitum var. imbricans)

Dorsal leaflet surface of Narrow-leaved Sword-fern, Imbricate Sword Fern: Polystichum imbricans ssp. imbricans (Synonym: Polystichum munitum var. imbricans) ----- Frond of Narrow-leaved Sword-fern, Imbricate Sword Fern: Polystichum imbricans ssp. imbricans (Synonym: Polystichum munitum var. imbricans)

The photo above show close-ups of imbricate sword fern as seen on a large lava outcrop on the uphill side of the Round the Mt. Trail #9 to the west of Shorthorn Creek in the Mt. Adams Wilderness.........................September 5, 2006. Lacelip fern (Cheilanthes gracillima), Cascade rockbrake (Cryptogramma cascadensis) and brittle fern (Cystopteris ffragilis) are also found at this location. Click each photo to see an enlarged version.

Paul Slichter