''Polystichum lemmonii'' 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 names Lemmon's holly fern and Shasta fern. It is native to western North America from the

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

north to

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

. It is also known from

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

, where there is a single occurrence in the mountains above the

Okanagan Valley The Okanagan ( ), also known as the Okanagan Valley and sometimes as the Okanagan Country, is a region in the Canadian province of British Columbia defined by the basin of Okanagan Lake and the Canadian portion of the Okanagan River. It is part ...

.Recovery strategy for the Lemmon's holly fern (''Polystichum lemmonii'') in British Columbia.
BC Ministry of Environment, July 2007.

Description

This fern produces several narrow, erect lance-shaped leaves 10 to 35 centimeters long. Each leaf (frond) is made up of many oval leaflets (pinnae) which are overlapping, folded, and twisted such that the leaves may appear almost cylindrical in outline. Leaflet margins are entire or bluntly dentate. Hitchcock, C.L. and Cronquist, A. 2018. Flora of the Pacific Northwest, 2nd Edition, p. 64. University of Washington Press, Seattle.Burke Herbarium Image Collection, http://biology.burke.washington.edu/herbarium/imagecollection/taxon.php?Taxon=Polystichum%20lemmonii

Habitat

''P. lemmonii'' grows in mountainous habitat on

ultramafic rock Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed ...

substrates, almost always in

serpentine soil Serpentine soil is an uncommon soil type produced by weathered ultramafic rock such as peridotite and its metamorphic derivatives such as serpentinite. More precisely, serpentine soil contains minerals of the serpentine subgroup, especially anti ...

s or among serpentine rocks. Though it grows in very restricted areas, ''P. lemmonii'' can be locally very abundant.

Gallery

Image:Polystichum lemmonii JHT IMG 7856.jpg, On ultramafic rock in Wenatchee Mountains Image:Polystichum lemmonii JHT IMG 7857.jpg, Adaxial (upper) leaf surface Image:Polystichum lemmonii JHT IMG 7860.jpg, Abaxial (lower) leaf surface with sori Image:Polystichum lemmonii JHT IMG 5370.jpg, On Bean Peak in Wenatchee Mountains

References

External links

Jepson Manual TreatmentPhoto gallery
lemmonii Ferns of California Flora of the Sierra Nevada (United States) {{Dryopteridaceae-stub