Christmas Fern

Polystichum acrostichoides

Christmas_Fern_Clifty_Creek_10-27-12.jpg

Photo of Christmas fern leaves lying against fallen oak leaves
Christmas fern is a perennial fern common on wooded slopes. Toward the end of the growing season, the evergreen leaves tend to lie flat on the ground.
Other Common Name
Holly Fern
Family

Dryopteridaceae (wood-ferns)

Description

Christmas fern is a perennial fern that bears two types of leaves (fronds). Leaves that produce spores have the spore-producing leaflets (pinnae) at the upper third of the frond; these fertile leaflets are notably smaller and thinner than the vegetative (non-spore-producing) leaflets on the basal portion of the frond. The fertile leaves usually stand more upright than the sterile leaves, and their smaller, spore-bearing leaflets usually wither by winter. The sterile leaves, lacking spore-producing pinnae, have a more regular appearance and are evergreen, lasting through the winter, often lying flat on the ground. The leaf stalks are green and have scales (they are not shiny). In spring, the fiddleheads (developing fronds) are scaled and silvery.

Looking more closely at the leathery, rich green leaves, the lance-shaped leaflets are spiny-toothed with bristle tips, looking something like holly leaves. Leaflets usually have an earlike lobe at the base of the upper side. The spore clusters are in rows of circular, umbrella-like structures, which can be so close together that they may cover nearly the entire leaflet undersurface. Spores are produced June–October.

Key Identifiers

 

  • Evergreen leaves that usually lie flat on the ground in winter
  • Leaflets sawtoothed with bristle tips
  • Leaflets with a basal earlike lobe on the upper side
  • On fertile fronds, spore-producing leaflets are at the top third of the frond and are noticeably smaller and thinner than the leaflets below
  • Spore clusters circular and usually crowded together
  • Stalks are scaly (not smooth and shiny), green or greenish (brownish at base)
Size

Leaves: 4 to 30 inches long; leaflets: usually 2 to 3 inches long.

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Photo of a big cluster of Christmas fern fronds lying on the ground
Christmas Fern
Christmas ferns grow like a bouquet. Late in the season they lay flat on the ground.

Christmas_Fern_pinnae_Clifty_Creek_10-27-12.jpg

Photo of Christmas fern, closeup showing pinnae
Christmas Fern Leaflets
The leaflets, or pinnae of Christmas fern are sawtoothed with bristle tips. They look a little like holly leaves. Also note the earlike lobe at the base on the top (apical) side of each pinna.

Christmas_Fern_Clifty_Creek_10-23-14.jpg

Photo of Christmas fern showing fertile frond (left) and vegetative frond
Christmas Fern at Clifty Creek CA
The fertile fronds of Christmas fern have noticeably smaller, spore-bearing leaflets on the upper third of the frond (at left).

Christmas_Fern_spores_Clifty_Creek_10-23-14.jpg

Photo of Christmas fern leaf underside showing spore clusters
Christmas Fern Spores
The spore clusters of Christmas fern are in rows of circular, umbrella-like structures. Sometimes, they are so close together they can cover nearly the entire leaflet undersurface.

Christmas_Ferns_Gans_Creek_11-6-10.jpg

Photo of a Christmas fern colony on a fall-leaf-covered slope along Gans Creek
Christmas Ferns at Gans Creek
By mid-November, Christmas fern may be one of the few green plants still visible on wooded slopes. They stay green all winter long.

Christmas_fern_fiddlehead_Clifty_Creek_4-20-13.jpg

Photo of a developing Christmas fern frond
Christmas Fern Fiddlehead
The fiddleheads (crosiers) of developing Christmas fern fronds are silvery and scaled. Look for them in the woods in April.

Christmas_Fern_Whetstone_Creek_1-1998.jpg

Photo of green Christmas fern fronds holding snow
Christmas Fern in Snow
Pioneers used the holly-like evergreen leaves of Christmas fern to make Christmas wreaths, hence the name.

Christmas_Fern_fiddlehead_closeup_4-2000.jpg

Closeup photo of a Christmas fern fiddlehead
Christmas Fern Crosier
Christmas fern fronds develop as “fiddleheads” in spring. They stay green through the winter.
Habitat and conservation

Occurs on wooded slopes in both dry and moist substrates, usually in shady or somewhat shady areas. One of the most common ferns in Missouri’s forests and woodlands.

Distribution in Missouri

Statewide.

Life cycle

Christmas ferns, like other ferns, have a two-parted life cycle. The plant we usually see is called a sporophyte, because it produces spores. Spores, produced on the undersides of the leaves, are extremely small seedlike packages of genetic material that can blow in the wind or be carried by water. When the spores germinate, they become the other part of the life cycle, the gametophyte. The gametophyte is a tiny, flat, green, heart- or kidney-shaped plant that bears organs that produce eggs and sperm. The sperm must swim to reach the eggs, so liquid water must be present for fertilization to occur. The fertilized eggs then develop into new sporophyte plants — the ferns we are accustomed to seeing.

Human connections

Pioneers used the holly-like evergreen leaves of this fern to make Christmas wreaths, hence the name.

In cultivation, Christmas fern provides winter interest in woodland, shade, or native plant gardens, along walls, or on slopes. On slopes, it helps to prevent erosion. If you wish to plant Christmas fern, make sure you get your plants from reputable native plant dealers. Don’t dig them from the wild.

Ferns and their relatives dominated the landscape in the Carboniferous Period, about 300 million years ago. Through geologic processes, they, and the carbon they had taken from the air and trapped in their tissues, were transformed into coal. In a way, the coal we burn for energy is a plant resource — fossilized fern forests. When we burn coal, we are taking carbon that had been buried underground for millions of years and releasing it back into the atmosphere.

Ecosystem connections

During winter, the prostrate fronds of Christmas fern hold fallen leaves against the ground, speeding their decomposition and enriching the soil.

Christmas ferns and other plants help to stabilize soils on slopes, preventing erosion.

Not many animals eat the leaves of Christmas fern.

Like other evergreen plants, Christmas fern can conduct photosynthesis on warm winter days. Also, it can take advantage of sunny days in early spring and late fall, when leafless trees permit sunshine to reach the forest floor.