''Polystichum lonchitis'' is a species of

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...

known by the common name northern hollyfern, or simply holly-fern. It is native to much of the Northern Hemisphere from Eurasia to

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...

and south into mountainous central North America. It has stiff, glossy green, erect fronds and grows in moist, shady, rocky mountain habitats.

Description

This tufted fern produces several erect, linear fronds up to long. In shadier locations fronds may be held horizontally. The fronds are glossy and stiff, pinnate, with many lance-shaped to oblong pinnae (leaflets) up to long, the longest ones occurring near the midpoint of the frond, the basal ones being smaller and triangular in shape. The pinnae overlap each other slightly and are toothed with prominent outward-pointing spines on the margins. The sori are rounded, with a whitish to gray covering (

indusium A sorus (pl. sori) is a cluster of sporangia (structures producing and containing spores) in ferns and fungi. A coenosorus (plural coenosori) is a compound sorus composed of multiple, fused sori. Etymology This New Latin word is from Ancient ...

), and are arranged in two rows on the underside of the pinnae. Hitchcock, C.L. and Cronquist, A. 2018. Flora of the Pacific Northwest, 2nd Edition, p. 63. University of Washington Press, Seattle. This is a slow-growing, long-lived plant.

Distribution and habitat

Holly fern is an arctic-alpine species with a circumpolar boreal and montane distribution in the Northern Hemisphere. It grows best in calcareous soil in cool, damp locations at the base of cliffs, on rock ledges and crevices, and among boulders and in deep cavities in

limestone pavement A limestone pavement is a natural karst landform consisting of a flat, incised surface of exposed limestone that resembles an artificial pavement. The term is mainly used in the UK and Ireland, where many of these landforms have developed dist ...

s. It also grows on other types of rocks as long as they are not calcium deficient. In the British Isles it occurs in Scotland and the western fringes of England, Wales and Ireland, and at scattered locations elsewhere. It occurs at a single location in Northern Ireland, at Lough Navar Forest Park in

County Fermanagh County Fermanagh ( ; ) is one of the thirty-two counties of Ireland, one of the nine counties of Ulster and one of the six counties of Northern Ireland. The county covers an area of 1,691 km2 (653 sq mi) and has a population of 61,805 a ...

, and because of its rarity there, it is listed as a Northern Ireland Priority Species.

Gallery

Image:Polystichum lonchitis JHT IMG 5801.jpg, Growing near Snoqualmie Pass Image:Polystichum lonchitis JHT IMG 5803.jpg, Abaxial (lower) leaf surface with sori

References

External links

Jepson Manual TreatmentFlora of North AmericaPhoto gallery
{{Taxonbar, from=Q542735 lonchitis