Polystichum

Polystichum is a genus of ferns in the family Dryopteridaceae, subfamily Dryopteridoideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I).[1] The genus has about 500 species and has a cosmopolitan distribution.[1][3] The highest diversity is in eastern Asia, with about 208 species in China alone;[3] the region from Mexico to Brazil has at least 100 additional species; Africa (at least 17 species), North America (at least 18 species), and Europe (at least 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). They often are found in disturbed habitat such as road cuts, talus slopes, and stream banks.[4]

Polystichum
Polystichum setiferum0.jpg
Polystichum setiferum
Scientific classification e
Kingdom: Plantae
Clade: Tracheophytes
Class: Polypodiopsida
Order: Polypodiales
Suborder: Polypodiineae
Family: Dryopteridaceae
Subfamily: Dryopteridoideae
Genus: Polystichum
Roth[1]
Species

See text.

Synonyms[2]
  • Acropelta T.Nakai
  • Adenoderris J.Sm.
  • Aetopteron Ehrh. ex House
  • Hemesteum H.Lév.
  • Hypopeltis Michx.
  • Papuapteris C. Chr.
  • Phanerophlebia C. Presl
  • Plecosorus Fée
  • Sorolepidium Christ

DescriptionEdit

Many ferns of this genus have stout, slowly creeping rootstocks that form a crown, with a vase-like ring of evergreen fronds 30 to 200 centimetres (10 to 80 in) long. The sori are round, with a circular indusium, except in South American species which lack an indusium.[5] The stipes have prominent scales with often have hair-like cilia, but lack any true hairs.[5] The genus differs from the well-known and allied fern genus Dryopteris in the indusium being circular, not reniform, and in having the leaf segments with auricles—asymmetrical blades where one side of the segment is much longer than the other at the base.

ApomixisEdit

Apomixis, the development of an embryo without the occurrence of fertilization, is particularly common among ferns. Apomixis evolved several times independently in three different clades of polystichoid ferns.[6]

TaxonomyEdit

Polystichum is one of the 10 largest fern genera and is grouped within the Dryopteridaceae.[7] Polystichum s.l. is well defined as its own monophyletic group, including species from the genera Cyrtomidictyum, Cyrtogonellum, Cyrtomium, and Phanerophlebia.[8] Research concerning taxonomy within Polystichum s.s. is ongoing, with high levels of hybridization, allopolyploidy, and apomixis making distinctions difficult.[9] Based on genetic analysis Little & Barrington (2003) originally defined a monophyletic Polystichum s.s. by removing Cyrtomium as its own genus.[4] It was further separated by Li et al. (2008) into a separate clade along with Phanerophlebia.[10]

Selected speciesEdit

The genus has a large number of species. The PPG I classification suggested that there were about 500 species;[1] as of February 2020, the Checklist of Ferns and Lycophytes of the World listed 397 species and 58 hybrids, noting that "many undescribed species remain".[11] The genus Polystichum includes, but is not limited to, the following species. In this list, a species name preceded by (=) is considered to be a synonym of the accepted species name above it.

HybridsEdit

Hybridisation is frequent in the genus, with several named hybrids, including:-

  • P. × bicknellii (P. aculeatum × P. setiferum)
  • P. × illyricum (P. aculeatum × P. lonchitis)
  • P. × lonchitiforme (P. lonchitis × P. setiferum)
  • P. × lesliei (P. setiferum × P. munitum) first found in Surrey in 1995 and a second plant found in Cornwall in 2001.[41]

Former speciesEdit

Species that were at one time considered part of the genus Polystichum, but are now categorized elsewhere, include:

DistributionEdit

With species in six continents and many islands, Polystichum is remarkable for its global spread. Polystichum ferns first emerged in Asia during the late Eocene, around 49 million years ago.[3] During this period there were high temperatures across the globe, which may have contributed to the diversification of flora.[45]

Polystichum's spread to the New World took place during the late Eocene to early Oligocene. The most likely dispersal method was across a paratropical forest on a Pacific Ocean land bridge, such as the Bering Land Bridge.[3] For a period before the height of the Ice Age temperatures froze enough seawater to lower the sea level but still allowed a forest to grow in Northern latitudes. From there Polystichum was able to spread through North American and into Central America.

Original theories described Polystichum spreading further into South America from Central America, but recent research has shown that South American Polystichum instead spread through long-distance dispersal from Australia. Genetic study has revealed close evolutionary relationships between Polystichum species in these two areas. Both Austral and Austral South American species lack and indusium. Austral Polystichum lack cilia, while South American species have marginal cilia.[46]

Hawaiian Polystichum also spread through long-distance dispersal, with two separate dispersal events leading to the three Polystichum now observed in Hawaii.[9]

EcologyEdit

Polystichum species are used as food plants by the larvae of some Lepidoptera species including Pharmacis fusconebulosa. Specimens of some of these can be found at the Royal Botanic Gardens, Sydney.

CultivationEdit

Several species are grown as ornamental plants in gardens, notably P. setiferum. One species, P. tsus-simense of eastern Asia, is commonly offered as a houseplant.

ReferencesEdit

  1. ^ a b c d PPG I (2016), "A community-derived classification for extant lycophytes and ferns", Journal of Systematics and Evolution, 54 (6): 563–603, doi:10.1111/jse.12229
  2. ^ Synonyms Tropicos.org. Missouri Botanical Garden. 25 Jan 2012
  3. ^ a b c d Le Péchon, Timothée; Zhang, Liang; He, Hai; Zhou, Xin-Mao; Bytebier, Benny; Gao, Xin-Fen; Zhang, Li-Bing (2016-05-01). "A well-sampled phylogenetic analysis of the polystichoid ferns (Dryopteridaceae) suggests a complex biogeographical history involving both boreotropical migrations and recent transoceanic dispersals". Molecular Phylogenetics and Evolution. 98: 324–336. doi:10.1016/j.ympev.2016.02.018. ISSN 1055-7903. PMID 26944012.
  4. ^ a b Little, D. P.; Barrington, D. S. (2003-03-01). "Major evolutionary events in the origin and diversification of the fern genus Polystichum (Dryopteridaceae)". American Journal of Botany. 90 (3): 508–514. doi:10.3732/ajb.90.3.508. ISSN 0002-9122. PMID 21659143.
  5. ^ a b "Polystichum Homepage". www.uvm.edu. Retrieved 2019-12-17.
  6. ^ Hong-Mei Liu, Robert J. Dyer, Zhi-You Guo, Zhen Meng,Jian-Hui Li, Harald Schneider (2012) The Evolutionary Dynamics of Apomixis in Ferns: A Case Study from Polystichoid Ferns Journal of Botany Volume 2012 (2012), Article ID 510478, 11 pages https://dx.doi.org/10.1155/2012/510478
  7. ^ Little, Damon P.; Barrington, David S. (2003). "Major evolutionary events in the origin and diversification of the fern genus Polystichum (Dryopteridaceae)". American Journal of Botany. 90 (3): 508–514. doi:10.3732/ajb.90.3.508. ISSN 1537-2197. PMID 21659143.
  8. ^ Li, Chun-xiang; Lu, Shu-gang; Barrington, David S. (2008-01-01). "Phylogeny of Chinese Polystichum (Dryopteridaceae) based on chloroplast DNA sequence data (trnL-F and rps4-trnS)". Journal of Plant Research. 121 (1): 19–26. doi:10.1007/s10265-007-0120-1. ISSN 1618-0860. PMID 18000642.
  9. ^ a b Driscoll, H. E.; Barrington, D. S. (2007-08-01). "Origin of Hawaiian Polystichum (Dryopteridaceae) in the context of a world phylogeny". American Journal of Botany. 94 (8): 1413–1424. doi:10.3732/ajb.94.8.1413. ISSN 0002-9122. PMID 21636509.
  10. ^ Li, Chun-xiang; Lu, Shu-gang; Barrington, David S. (January 2008). "Phylogeny of Chinese Polystichum (Dryopteridaceae) based on chloroplast DNA sequence data (trnL-F and rps4-trnS)". Journal of Plant Research. 121 (1): 19–26. doi:10.1007/s10265-007-0120-1. ISSN 0918-9440. PMID 18000642.
  11. ^ Hassler, Michael & Schmitt, Bernd (January 2020), "Polystichum", Checklist of Ferns and Lycophytes of the World, 8.20, retrieved 2020-02-02
  12. ^ "Polystichum andersonii". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 19 Jan 2012.
  13. ^ P. bonseyi Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  14. ^ "Polystichum bonseyi". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 19 Jan 2012.
  15. ^ "Polystichum brachypterum". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 19 Jan 2012.
  16. ^ "Polystichum braunii". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 19 Jan 2012.
  17. ^ P. brachypterum Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  18. ^ P. capillipes Tropicos.org. Missouri Botanical Garden. 20 Jan 2012
  19. ^ P. echinatum, Tropicos.org. Missouri Botanical Garden., 19 Jan 2012
  20. ^ P. kiusiuense Tropicos.org. Missouri Botanical Garden. 20 Jan 2012
  21. ^ "Polystichum haleakalense". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 19 Jan 2012.
  22. ^ Conspectus of Southern African Pteridophyta, J. P. Roux, Nov. 2001. p. 129
  23. ^ P. mollissimum Tropicos.org. Missouri Botanical Garden. 20 Jan 2012
  24. ^ P. nakenense Chinese Plant Names www.eFloras.org 20 Dec 2012
  25. ^ P. neolobatum Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  26. ^ P. ordinatum Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  27. ^ P. erinaceum Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  28. ^ P. brunneum Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  29. ^ "Polystichum setigerum". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 20 Jan 2012.
  30. ^ P. lichiangense Tropicos.org. Missouri Botanical Garden. 20 Jan 2012
  31. ^ P. sinense Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  32. ^ P. apicisterile Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  33. ^ P. integripinnulum Tropicos.org. Missouri Botanical Garden. 20 Jan 2012
  34. ^ P. conaense Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  35. ^ P. ilicifolium Tropicos.org. Missouri Botanical Garden. 20 Jan 2012
  36. ^ P. heteropaleaceum Tropicos.org. Missouri Botanical Garden. 20 Jan 2012
  37. ^ P. kodamae Tropicos.org. Missouri Botanical Garden. 20 Jan 2012
  38. ^ P. xiphophyllum Tropicos.org. Missouri Botanical Garden. 20 Jan 2012
  39. ^ P. gyirongense Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  40. ^ P. jizhushanense Tropicos.org. Missouri Botanical Garden. 20 Jan 2012
  41. ^ Murphy, Rosaline J; Page, Christopher N; Parslow, Rosemary E; Bennallick, Ian J (2012). Ferns, Clubmosses, Quillworts and Horsetails of Cornwall and the Isles of Scilly. Truro: ERCCIS. ISBN 978-1-902864-07-5.
  42. ^ P. auriculatum Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  43. ^ P. falcatum Tropicos.org. Missouri Botanical Garden. 19 Jan 2012
  44. ^ P. lepidocaulon Tropicos.org. Missouri Botanical Garden. 20 Jan 2012
  45. ^ LI, Chunxiang (2004). "Asian origin for Polystichum (Dryopteridaceae) based on rbcL sequences". Chinese Science Bulletin. 49 (11): 1146. Bibcode:2004ChSBu..49.1146L. doi:10.1360/04wc0086. ISSN 1001-6538.
  46. ^ Morero, Rita E.; Deanna, Rocío; Barboza, Gloria E.; Barrington, David S. (August 2019). "Historical biogeography of the fern genus Polystichum (Dryopteridaceae) in Austral South America". Molecular Phylogenetics and Evolution. 137: 168–189. doi:10.1016/j.ympev.2019.05.004.

External linksEdit