Polystichum is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of about 260 species of fern

Fern

A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...

s with a cosmopolitan distribution

Cosmopolitan distribution

In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...

. The highest diversity is in eastern Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, with about 120 species in China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 alone; the region from Mexico to Brazil has nearly 100 additional species; Africa

Africa

Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 (17 species), North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 (15 species), and Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 (5 species) have much lower diversity. Polystichum species are terrestrial or rock-dwelling ferns of warm-temperate and montane-tropical regions (a few species grow in alpine regions).

Many ferns of this genus have stout, slowly-creeping rootstocks that form a crown, with a vase-like ring of evergreen

Evergreen

In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

 frond

Frond

The term frond refers to a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group...

s 30-200 cm long. The sori

Sorus

A sorus is a cluster of sporangia .In fungi and lichens, the sorus is surrounded by an external layer. In some red algae it may take the form of a depression into the thallus....

 are round, with a circular indusium. The stipes have prominent scales. The genus differs from Dryopteris

Dryopteris

Dryopteris , commonly called wood ferns, male ferns, and buckler ferns, is a genus of about 250 species of ferns with distribution in the temperate Northern Hemisphere, with the highest species diversity in eastern Asia. Many of the species have stout, slowly creeping rootstocks that form a crown,...

in the indusium being circular, not reniform, and in having stronger, more persistent fronds with a harder, somewhat rough, texture.

Hybridisation is frequent in the genus, with several named hybrids.

Several species are grown as ornamental plant

Ornamental plant

Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...

s in gardens. One species, Polystichum tsus-simense of eastern Asia, is a commonly offered house plant.

Polystichum species are used as food plants by the larva

Larva

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e of some Lepidoptera

Lepidoptera

Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...

 species including Pharmacis fusconebulosa. Specimens of some of these can be found at the Royal Botanic Gardens, Sydney

Royal Botanic Gardens, Sydney

The Royal Botanic Gardens in Sydney, Australia, are the most central of the three major botanical gardens open to the public in Sydney....

.

Selected species

Polystichum acanthophyllum Polystichum acrostichoides Polystichum acrostichoides Polystichum acrostichoides is an evergreen fern native to eastern North America from Nova Scotia west to Minnesota and south to Florida and eastern Texas... - Christmas Fern Polystichum aculeatum Polystichum aculeatum Polystichum aculeatum is an evergreen fern native to Europe. It is most abundant in upland regions of the British Isles and western France, where it benefits from the combination of mild winters and moist summers, but also occurs more locally across most of Europe except northern Scandinavia,... - Hard Shield Fern Polystichum acutidens Polystichum acutipinnulum Polystichum alcicorne Polystichum aleuticum Polystichum aleuticum Polystichum aleuticum, the Aleutian Shield Fern, is an endangered species of the Polystichum genus and currently consisting of a small, vulnerable population endemic and existing only on Adak Island, Alaska, a remote island of the Aleutian Islands chain in the northern Pacific Ocean... Polystichum andersonii Polystichum apici-sterile Polystichum assurgens Polystichum atkinsonii Polystichum atuntzeense Polystichum auriculatum Polystichum australiense Polystichum austro-tibeticum Polystichum bakerianum Polystichum biaristatum Polystichum bicolor Polystichum bomiense Polystichum brachypterum Polystichum braunii - Braun's Shield Fern Polystichum brunneum Polystichum calderonense Polystichum calderonense Polystichum calderonense is a rare species of fern known by the common name Monte Guilarte hollyfern. It is endemic to Puerto Rico, where it occurs in the Peñuelas and Guilarte Commonwealth Forests. There are only 57 individual plants remaining... Polystichum californicum Polystichum californicum Polystichum californicum is a species of fern known by the common name California sword fern. It is native to western North America from British Columbia to California, where it occurs in the coastal mountain ranges and the Cascade Range through the Sierra Nevada. Its habitat includes forest... Polystichum castaneum Polystichum christii Polystichum chunii Polystichum conaense Polystichum craspedosorum Polystichum cyclolobum Polystichum cystostegia Polystichum decorum Polystichum deltodon Polystichum dielsii Polystichum discretum Polystichum dudleyi Polystichum dudleyi Polystichum dudleyi is a species of fern known by the common name Dudley's sword fern. It is endemic to California, where it is known from the forests of the central and southern California Coast Ranges.-Description:... Polystichum duthiei Polystichum ellipticum Polystichum erinaceum Polystichum erosum Polystichum excellens Polystichum eximium Polystichum falcatipinnum Polystichum falcatum - Sickle-leaved Holly Fern Polystichum falcilobum Polystichum falcinellum Polystichum fallax Polystichum formosanum Polystichum garhwalicum Polystichum gongboense Polystichum gyirongense Polystichum gymnocarpum Polystichum hancockii Polystichum hecatopteron Polystichum herbaceum Polystichum ilicifolium Polystichum imbricans Polystichum imbricans Polystichum imbricans is a species of fern known by the common name narrowleaf sword fern. It is native to western North America from British Columbia to southern California, where it grows in rocky habitat in coastal and inland mountain ranges and foothills. This fern produces several erect linear... Polystichum incongruum Polystichum integripinnulum Polystichum jizhushanense Polystichum kiusiuense Polystichum kodamae Polystichum kruckebergii Polystichum kruckebergii Polystichum kruckebergii is a species of fern known by the common names Kruckeberg's sword fern and Kruckeberg's holly fern. It is native to western North America from Alaska to Utah to California, where it grows in rocky mountain habitat in subalpine and alpine climates.This fern produces several... Polystichum kwakiutlii Polystichum lachenense Polystichum lanceolatum Polystichum lemmonii Polystichum lemmonii Polystichum lemmonii is a species of fern known by the common names Lemmon's holly fern and Shasta fern. It is native to western North America from the Sierra Nevada of California north to Washington... Polystichum lentum Polystichum lepidocaulon Polystichum letum Polystichum lhasaense Polystichum lichiangense Polystichum lonchitis Polystichum lonchitis Polystichum lonchitis is a species of fern known by the common name northern holly fern, 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 grows in moist, shady, rocky mountain habitat. This... - Holly Fern Polystichum longidens Polystichum longipaleatum Polystichum longipes

Polystichum luctuosum - Mourning Shield Fern Polystichum macleae Polystichum macrochlaenum Polystichum makinoi Polystichum martini Polystichum mayebarae Polystichum mediocre Polystichum medogense Polystichum microchlamys Polystichum minusculum Polystichum mohrioides Polystichum mollissinum Polystichum monotis Polystichum monticola - Mountain Shield Fern Polystichum morii Polystichum moupinense Polystichum munitum Polystichum munitum Polystichum munitum is an evergreen fern native to western North America, where it is one of the most abundant ferns occurring along the Pacific coast from southeast Alaska south to southern California, and also inland east to southeastern British Columbia, northern Idaho and western Montana, with... - Western Sword Fern Polystichum muricatum Polystichum nakenense Polystichum neolobatum Polystichum nepalense Polystichum ningshenense Polystichum nyalamense Polystichum obliquum Polystichum omeiense Polystichum orientali-tibeticum Polystichum paradoxum Polystichum paramoupinense Polystichum parvipinnulum Polystichum piceopaleaceum Polystichum platychlamys Polystichum polyblepharum - Tassel Fern Polystichum prescottianum Polystichum prionolepis Polystichum proliferum Polystichum proliferum Polystichum proliferum is an Australian fern. Known by the common name Mother Shield Fern. It is found in cool moist areas of southern Australia. Seen at high altitude, where it may form large colonies. It grows in Tasmania, Victoria and as far north as Tenterfield, New South Wales... - Mother Shield fern Polystichum pseudo-castaneum Polystichum pseudomakinoi Polystichum pungens - Forest Shield Fern Polystichum qamdoense Polystichum rarum Polystichum retrorsopalaeceum Polystichum rhombiforme Polystichum rhomboideum Polystichum richardii Polystichum rigens Polystichum rotundilobum Polystichum scopulinum Polystichum scopulinum Polystichum scopulinum is a species of fern known by the common names mountain holly fern and rock sword fern. It is native to much of western North America, and it is known from disjunct occurrences in eastern Canada, as well. It grows in rocky habitat, often in full sun... Polystichum semifertile Polystichum setiferum Polystichum setiferum Polystichum setiferum is an evergreen or semi-evergreen fern native to southern and western Europe.-Distribution:... - Soft Shield Fern Polystichum setigerum Polystichum setosum Polystichum shensiense Polystichum silvaticum Polystichum simplicipinnum Polystichum sinense Polystichum squarrosum Polystichum stenophyllum Polystichum stimulans Polystichum submite Polystichum thomsoni Polystichum tialoshanense Polystichum tibeticum Polystichum transvaalense - Stemmed Shield Fern Polystichum tripteron Polystichum tsuchuense Polystichum tsus-simense - Korean Rock Fern Polystichum tumbatzense Polystichum vestitum Polystichum vestitum Polystichum vestitum, commonly known as the Prickly Shield Fern, is a hardy, evergreen or semi-evergreen ground fern.-Description:... - Prickly Shield Fern Polystichum virescens Polystichum watii Polystichum wilsoni Polystichum wuyishanense Polystichum xiphophyllum Polystichum yadongense Polystichum yigongense

Selected hybrids

• Polystichum × bicknellii (P. aculeatum × P. setiferum)
• Polystichum × illyricum (P. aculeatum × P. lonchitis)
• Polystichum × lonchitiforme (P. lonchitis × P. setiferum)

External links

• Jepson Manual Treatment

• the Polystichum homepage