Map Snapshot
2,068 Records
Status
Christmas fern occurs in northeastern and north-central parts of North America from New Brunswick south to North Carolina. It is hardy and abundant and has been documented in every county in Maryland.
Description
“Lustrous, dark green fronds in circular, arching clumps from central rhizome" (Cobb, Farnsworth, and Lowe, 2005). Because Christmas Ferns are evergreen, they are evident all year round, including at Christmas-time, which may be one reason for their name. The margins of each leaflet, or pinna, has narrow fine teeth. A boot-like projection at the pinna base suggests a Christmas stocking, which is a helpful identification feature. Christmas Ferns have both sterile and fertile fronds, the fertile ones bearing markedly shorter, narrower pinnae near their tips. These smaller pinnae, which have tan spore cases (sori) on their undersides, are most noticeable in late summer and fall. Then the spores are shed and the pinnae that bore them dry up, while the rest of the frond remains green. The dry pinnae give the fern a diseased look, but this is the natural condition of the fronds after spore release.
Where To Find
Christmas Fern is especially common on slopes and banks of streams. It is easily observed in winter, when most other green forest-floor plants have died back for the year.
Relationships
"Growing ferns and the accumulated detritus of past sterile fronds form a dense covering mass over the soil surface. This mass helps to stabilize the underlying soil and prevent or lessen erosion. It also generates a protective, concealing habitat for a number of ground feeding and ground nesting bird species.
"Because of their complex chemical composition, ferns are eaten by very few browsers or grazers. Fern densities in general have been increasing in many of the forests of Pennsylvania [and presumably of Maryland, too], due to the removal of competing, but more palatable, under-story plant species by the extensive browsing by the state's rapidly increasing deer population. This change in the forest under-story habitat structure has had wide-spread and deleterious impacts on the densities and successes of some mid-canopy birds (like the least flycatcher and the yellow billed cuckoo). Other bird species (like the wild turkey, for example) that use the concealing fern masses for their nesting sites have, however, increased in density in these "fern park" forests" (Penn State, Christmas Fern).
Seasonality Snapshot
Source: Wikipedia
| Polystichum acrostichoides | |
|---|---|
| |
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Division: | Polypodiophyta |
| Class: | Polypodiopsida |
| Order: | Polypodiales |
| Suborder: | Polypodiineae |
| Family: | Dryopteridaceae |
| Genus: | Polystichum |
| Species: | P. acrostichoides
|
| Binomial name | |
| Polystichum acrostichoides | |
| |
| Native range of Christmas fern in the United States | |
| Synonyms[2] | |
|
Nephrodium acrostichoides Michx. | |
Polystichum acrostichoides, commonly denominated Christmas fern, is a perennial, evergreen fern native to eastern North America, from Nova Scotia west to Minnesota and south to Florida and eastern Texas.[3] It is one of the most common ferns in eastern North America, being found in moist and shady habitats in woodlands, stream banks and rocky slopes. The common name derives from the evergreen fronds, which are often still green at Christmas.
Description
[edit]Christmas fern has a tufted, clumping habit, with its fronds arising from a central growth point. It can form colonies, but frequently grows singly or in twos or threes.[4] In winter, the fertile fronds die; the sterile fronds remain through the winter, and are often flattened to the ground by low temperatures and snow cover. The frond is supported by a dark brown- to black-colored stipe, or stem, which is typically a quarter to a third of the overall frond length.[4] Coarse, light-brown-to-tan scales cover the stipe, and are typically about 5-millimetre-long (0.20 in) and translucent. The coiled, developing fronds ("crosiers") are scaly, greyish and prominent in early spring.[4]
Fronds are 30-to-80-centimetre-long (12 to 31 in) and 5-to-12-centimetre-broad (2.0 to 4.7 in), dark green and rather leathery in texture; their undersides may be covered in very sparse hairs. They have 20 to 35 pairs of pinnae. Each pinna is typically 4-centimetre-long (1.6 in) and has a finely serrulate or spiny edge, and is oblong to falcate in shape. The fine teeth or spines on the edge of the pinna are oriented towards its tip. Each pinna has a small, triangular, "thumblike" lobe at its base.[5] The light brown spores are produced on fertile pinnae, at the frond's tip, which are conspicuously smaller than the sterile pinnae further down the frond.[6] These fertile pinnae can be described as "acrostichoid", given that the sporangia occupy most of the lower surface of the pinna.[7]
Christmas fern resembles the Pacific Coast sword fern, Polystichum munitum, although forming less expansive tufts and differing from it and from almost all other ferns in that fertile pinnae of the Christmas fern are noticeably reduced in size relative to the sterile pinnae, while being located on the same frond.
P. acrostichoides is known to hybridize with Polystichum braunii in areas where their ranges overlap.[5]
Ecology
[edit]P. acrostichoides is parasitized by the fungus Taphrina polystichi, which causes yellowish to whitish galls on the fronds.[8]
The moth Herpetogramma sphingealis has larvae that feed on Christmas ferns. This moth species is primarily found where Christmas ferns are abundant and was given a scientific description in 2011.[9]
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Polystichum acrostichoides growing in Tiadaghton State Forest, Lycoming County, along the Golden Eagle Trail.
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Cultivation
[edit]Christmas fern is popular in cultivation as an ornamental plant for gardens, including natural gardens, as it is easy to cultivate in a range of environments and soils. Being evergreen, it is sometimes used in winter-oriented garden design.[10]
This fern can conserve soil and allay erosion of steep slopes. The fronds are semi-erect until the first killing frost, after which they lie prostrate on the ground and effectively hold in place the duff layer of the forest floor, enabling the gradual decomposition of the duff into humus, which in turn builds the soil.
Gallery
[edit]-
Coiled immature fronds -
Newly unfurled frond -
Mature sterile frond -
Sori
References
[edit]- ^ "NatureServe Explorer 2.0 - Polystichum acrostichoides Christmas Fern". explorer.natureserve.org. Retrieved 9 October 2020.
- ^ "Tropicos | Name - Polystichum acrostichoides (Michx.) Schott". www.tropicos.org. Retrieved 26 June 2016.
- ^ USDA, accessed 2011.
- ^ a b c Foster, Boughten Cobb (1987). A field guide to ferns and their related families of Northeastern and Central North America with a section on species also found in the British Isles and Western Europe. Illustrated by Laura Louise ([New ed., pbk. ed.]. ed.). Boston: Houghton Mifflin. ISBN 0-395-19431-8.
- ^ a b Rhoads, Ann; Block, Timothy (2007-09-05). The Plants of Pennsylvania (2 ed.). Philadelphia Pa: University of Pennsylvania press. ISBN 978-0-8122-4003-0.
- ^ "Taxon Page". www.efloras.org. Retrieved 26 June 2016.
- ^ Coulter, John (1917). The Botanical Gazette (volume LXIV). p. 347. Retrieved 26 June 2016.
- ^ Mix, A.J. (1938). "Some Taphrina on North American ferns". Mycologia. 30: 563–579. doi:10.1080/00275514.1938.12017299.
- ^ Handfield, Louis; Handfield, Daniel (24 November 2011). "A New Species of Herpetogramma (Lepidoptera, Crambidae, Spilomelinae) from Eastern North America". ZooKeys (149): 5–15. Bibcode:2011ZooK..149....5H. doi:10.3897/zookeys.149.2344. PMC 3234405. PMID 22207790.
- ^ "Polystichum acrostichoides - Plant Finder". www.missouribotanicalgarden.org. Retrieved 2016-03-26.
- "Polystichum acrostichoides". Integrated Taxonomic Information System. Retrieved September 25, 2006.
External links
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