Polystichum lonchitis is a species of fern known by the common name northern hollyfern, or simply holly-fern. It is native to much of the Northern Hemisphere from Eurasia to Alaska to Greenland and south into mountainous central North America. It has stiff, glossy green, erect fronds and grows in moist, shady, rocky mountain habitats.
|Polystichum lonchitis in Mount Baker-Snoqualmie National Forest|
This tufted fern produces several erect, linear fronds up to 60 centimetres (24 in) long. The fronds are glossy and stiff, pinnate, with many lance-shaped to oblong pinnae (leaflets) up to 3 or 4 centimetres (1.2 or 1.6 in) 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 outward-pointing spiny margins. The sori are rounded, with a white covering, and are arranged in two rows on the underside of the pinnae.  This is a slow-growing, long-lived plant.
Distribution and habitatEdit
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, among boulders and in deep cavities in limestone pavements. 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, and because of its rarity there, it is listed as a Northern Ireland Priority Species.
- "Polystichum lonchitis". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 31 January 2016.
- "BSBI List 2007". Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-01-25. Retrieved 2014-10-17.
- Farmer, Carl. "Holly fern: Polystichum lonchitis". West Highland Flora. Retrieved 10 March 2020.
- Northridge, Robert. "Polystichum lonchitis – holly-fern". Northern Ireland Priority Species. Retrieved 10 March 2020.
- "Polystichum lonchitis". Online Atlas of the British and Irish Flora. Retrieved 10 March 2020.
Media related to Polystichum lonchitis at Wikimedia Commons