Polystichum acrostichoides (Christmas Fern)

Polystichum acrostichoides

Polystichum acrostichoides (Michx.) Schott

Christmas Fern

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Pteridophyta	Ferns
Class	Filicopsida	“Leptosporangiate” (has to do with how their spores form) ferns—includes most ferns
Order	Polypodiales	Polypod ferns
Family	Dryopteridaceae	Wood ferns (about 70% of the ferns)
Genus	Polystichum	From the Greek polys, “many,” and stichos, “row,” referring to the rows of sori on the type species
Species	acrostichoides	Like genus Acostichum

About plant names...

Christmas ferns are common and rugged, found in woodlands and shady, rocky slopes, in both moist and dry settings. They are so named because they remain green through the winter. They are native to eastern North America.

Identification: Like many ferns, fronds arise from a central root system, expanding outward in a funnel shape. Each stem (rachis) is very scaly, dark brown at the base, fading to green further up. Fronds are dark green and shiny. These ferns are mostly evergreen, looking flattened and bedraggled but otherwise intact in the winter. Fronds are 12-31" (30-80 cm) × 1¾-4½" (5-12 cm), lanceolate, usually tapering rapidly above the middle. Only the upper portion of fertile fronds bear spores—this portion is significantly smaller. Each frond contains 20-40 pinnae (leaflets). The pinnae, each about 1½" (4 cm) long, are also lanceolate, but with a distinctive bump on one side of the base, and fine teeth or spines along the leaf edges. The fiddleheads, called crosiers, are silvery and scaled.

Online References:

Polystichum acrostichoides on www.psu.edu

Polystichum acrostichoides on Wikipedia

Polystichum acrostichoides on the Connecticut Botanical Society's Connecticut wildflowers site

Polystichum acrostichoides at the Missouri Botanical Garden

Polystichum acrostichoides on the New England Wildflower Society’s GoBotany site

References:

Cobb, Boughton, Farnsworth, Elizabeth & Lowe, Cheryl, Peterson Field Guides: A Field Guide to Ferns and Their Related Families of Northwestern and Central North America, Houghton Mifflin Company, 2005, p. 198

Sterile pinnae. · 9/15/2012 · Mt. Wachusett, Princeton, MA
≈ 11 × 7" (27 × 18 cm)

7/5/2010 · Tarrywile Park and Mansion, Danbury, CT
≈ 17 × 14" (42 × 34 cm)

4/29/2010 · Bruce Freeman Rail Trail, Chelmsford, MA
≈ 15 × 10" (39 × 26 cm)

7/19/2012 · Beaver Brook Association Conservation Lands, Hollis, NH
≈ 14 × 9" (35 × 23 cm)

8/24/2009 · Tom and Susan’s, Pepperell, MA
≈ 2½ × 3½" (6.6 × 9.8 cm)

Crested form. · 9/6/2018

Sterile pinnae. · 9/15/2012 · Mt. Wachusett, Princeton, MA
≈ 12 × 8" (31 × 20 cm)

Polystichum acrostichoides description by Thomas H. Kent, last updated 12 Oct 2018.

5/23/2016 · Wildflower Trail, Beaver Brook Conservation Area, Hollis, NH

8/23/2009 · Tom and Susan’s, Pepperell, MA
≈ 17 × 12" (44 × 29 cm)

8/23/2009 · Tom and Susan’s, Pepperell, MA
≈ 4½ × 7" (11 × 17 cm)

7/5/2010 · Tarrywile Park and Mansion, Danbury, CT
≈ 21 × 14" (52 × 34 cm)

Incised form. · 9/14/2010 · Garden in the Woods, Framingham, MA
≈ 3 × 4½" (7.9 × 11 cm)

8/24/2009 · Tom and Susan’s, Pepperell, MA
≈ 4½ × 7" (11 × 17 cm)

8/23/2009 · Tom and Susan’s, Pepperell, MA
≈ 17 × 12" (44 × 29 cm)

The smaller pinnae near the end of the frond are the fertile ones. · 9/15/2012 · Mt. Wachusett, Princeton, MA
≈ 9 × 6" (23 × 15 cm)

Incised form. · 9/14/2010 · Garden in the Woods, Framingham, MA
≈ 21 × 14" (52 × 34 cm)

8/23/2009 · Tom and Susan’s, Pepperell, MA
≈ 4 × 6" (10 × 15 cm)

5/23/2016 · Wildflower Trail, Beaver Brook Conservation Area, Hollis, NH

8/23/2009 · Tom and Susan’s, Pepperell, MA
≈ 4½ × 7" (11 × 17 cm)

8/23/2009 · Tom and Susan’s, Pepperell, MA
≈ 4 × 6" (10 × 15 cm)

Range: Zones 3-9:

About this map...