Eriosorus and Jamesonia are two closely related genera in the taenitoid group of the core pteridoid ferns. They have long been recognized as being closely related, and recent genetic evidence has demonstrated that they are both paraphyletic genera, but only in regards to each other. Thus, they must be combined as a single larger genus, or have the generic boundaries redefined. The two genera are being temporarily considered here under Jamesonia, because 1) this is the older genus name, and 2) the core genus forms a clearly defined monophyletic group considered by itself, while there is no such clear clade for Eriosorus.

A new genus name, Eriosona, was described in 1977 to recognize the hybrids between these two genera. These hybrids are noted below. The frequency of such hybrids clearly points to the close relationships found in this group.

Eriosorus species are found in the cooler regions of Central

Central America

Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

 and South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, mainly in the Andes Mountains. The type species of Eriosorus is apparently Eriosorus aureonitens.

Jamesonia species are also found in cooler regions, but extending from Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 to Bolivia

Bolivia

Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

 and upland Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. The type species of Jamesonia is Jamesonia pulchra (or possibly Jamesonia imbricata, if this is found to be the same as J. pulchra).

Core Jamesonia clade

• Jamesonia alstonii A. Tryon
• Jamesonia brasiliensis Christ
  Konrad H. Christ
  Konrad Hermann Heinrich Christ , often known in citations as just "Christ" or "H. Christ", was a Swiss pteridologist botanist who specialized in ferns. He was a lecturer and professor of botany at Basel, Switzerland. The fern genus Christella is named in his honour.-Publications:*Christ, K. H. H....
  
  
• Jamesonia canescens (Klotzsch
  Johann Friedrich Klotzsch
  Johann Friedrich Klotzsch was a German pharmacist and botanist.His principal work was in the field of mycology, with the study and description of many species of mushroom.-Selected works:...
  
  ) Kze.
• Jamesonia imbricata (Cav.) Hook. & Grev.
• Jamesonia laxa Kze. ex Kuhn
  Kuhn
  Kuhn is a surname of German origin, derived from the Old German name Conrad. It may refer to the following people:* Abraham Kuhn , Alasatian otolaryngologist* Abraham Kuhn, American banker, founder of Kuhn, Loeb & Co....
  
  
• Jamesonia pulchra Hook. & Grev.
• Jamesonia rotundifolia Fée
  Antoine Laurent Apollinaire Fée
  Antoine Laurent Apollinaire Fée was a French botanist who was born in Ardentes, 7 November 1789, and died in Paris on 21 May 1874. He was the author of works on botany and mycology, practical and historical pharmacology, Darwinism, and his experiences in several regions of Europe.-Biography:Fée...
  
  
• Jamesonia scammanae A. Tryon

Jamesonia species in paraphyletic clades

• Jamesonia auriculata A. Tryon
• Jamesonia blepharum A. Tryon
• Jamesonia boliviensis A. Tryon
• Jamesonia cinnamomea Kze.
• Jamesonia crespiana Bosco
• Jamesonia cuatrecasasii A. Tryon
• Jamesonia goudotii (Hieron.) C. Chr.
• Jamesonia peruviana A. Tryon
• Jamesonia robusta Karst.
• Jamesonia scalaris Kze.
• Jamesonia verticalis Kze.

Eriosorus Species

• Eriosorus accrescens A. Tryon
• Eriosorus arenticola Schwartsburd & abiak/li>
• Eriosorus aureonitens (Hook.) Copel.
• Eriosorus biardii (ée) A. Tryon
• Eriosorus caracasanus (Baker
  Baker
  A baker is someone who bakes and sells bread, Cakes and similar foods may also be produced, as the traditional boundaries between what is produced by a baker as opposed to a pastry chef have blurred in recent decades...
  
  ) Vareschi
• Eriosorus cheilanthosis (Sw.
  Olof Swartz
  Olof Peter Swartz was a Swedish botanist and taxonomist. He is best known for his taxonomic work and studies into pteridophytes...
  
  ) A. Tryon
• Eriosorus congestus (Christ
  Christ
  Christ is the English term for the Greek meaning "the anointed one". It is a translation of the Hebrew , usually transliterated into English as Messiah or Mashiach...
  
  ) Copel.
• Eriosorus ewanii A. Tryon
• Eriosorus feei Copel.
• Eriosorus flexuousus (Humb. & Bonpl.) Copel.
• Eriosorus glaberrimus (Maxon
  William Ralph Maxon
  William Ralph Maxon, was an American botanist and pteridologist. He graduated from Syracuse University with a Ph.B. in 1898, and spent about one year at Columbia University doing post-graduate work on ferns with Lucien Marcus Underwood...
  
  ) Scamman
• Eriosorus glaziovii (C. Chr.) Copel.
• Eriosorus hirsutulus (Mett.) A. Tryon
• Eriosorus hirtus (H.B.K.) Copel.
• Eriosorus hispidulus (Kze.) Vareschi
• Eriosorus insignis (Kuhn
  Kuhn
  Kuhn is a surname of German origin, derived from the Old German name Conrad. It may refer to the following people:* Abraham Kuhn , Alasatian otolaryngologist* Abraham Kuhn, American banker, founder of Kuhn, Loeb & Co....
  
  ) A. Tryon
• Eriosorus lasseri Vareschi
• Eriosorus lechleri (Mett. ex Kuhn
  Kuhn
  Kuhn is a surname of German origin, derived from the Old German name Conrad. It may refer to the following people:* Abraham Kuhn , Alasatian otolaryngologist* Abraham Kuhn, American banker, founder of Kuhn, Loeb & Co....
  
  ) A. Tryon
• Eriosorus lindigii (Mett.) Vareschi
• Eriosorus longipetiolatus (Hieron.) A. Tryon
• Eriosorus myriophyllus(Swartz
  Olof Swartz
  Olof Peter Swartz was a Swedish botanist and taxonomist. He is best known for his taxonomic work and studies into pteridophytes...
  
  ) Copel.
• Eriosorus novogranatensis A. Tryon
• Eriosorus orbignyanus (Mett. ex Kuhn
  Kuhn
  Kuhn is a surname of German origin, derived from the Old German name Conrad. It may refer to the following people:* Abraham Kuhn , Alasatian otolaryngologist* Abraham Kuhn, American banker, founder of Kuhn, Loeb & Co....
  
  ) A. Tryon
• Eriosorus paucifolius (A. C. Smith) Vareschi
• Eriosorus retrofractus (Kze. ex Mett.) Crabbe
  George Crabbe
  George Crabbe was an English poet and naturalist.-Biography:He was born in Aldeburgh, Suffolk, the son of a tax collector, and developed his love of poetry as a child. In 1768, he was apprenticed to a local doctor, who taught him little, and in 1771 he changed masters and moved to Woodbridge...
  
  
• Eriosorus rufescens (Fée
  Antoine Laurent Apollinaire Fée
  Antoine Laurent Apollinaire Fée was a French botanist who was born in Ardentes, 7 November 1789, and died in Paris on 21 May 1874. He was the author of works on botany and mycology, practical and historical pharmacology, Darwinism, and his experiences in several regions of Europe.-Biography:Fée...
  
  ) A. Tryon
• Eriosorus sellowianus (Mett. ex Kuhn
  Kuhn
  Kuhn is a surname of German origin, derived from the Old German name Conrad. It may refer to the following people:* Abraham Kuhn , Alasatian otolaryngologist* Abraham Kuhn, American banker, founder of Kuhn, Loeb & Co....
  
  ) Copel.
• Eriosorus setulosus (Hieron.) A. Tryon
• Eriosorus stuebelii (Hieron.) A. Tryon
• Eriosorus velleus (Baker
  Baker
  A baker is someone who bakes and sells bread, Cakes and similar foods may also be produced, as the traditional boundaries between what is produced by a baker as opposed to a pastry chef have blurred in recent decades...
  
  ) A. Tryon
• Eriosorus villosulus (Maxon
  William Ralph Maxon
  William Ralph Maxon, was an American botanist and pteridologist. He graduated from Syracuse University with a Ph.B. in 1898, and spent about one year at Columbia University doing post-graduate work on ferns with Lucien Marcus Underwood...
  
  ) Scamman
• Eriosorus warscewiczii (Mett. in Triana
  José Jéronimo Triana
  José Jerónimo Triana Silva was a Colombian botanist who catalogued 60,000 specimens representing 8,000 species.For example:* Acisanthera alsinaefolia Triana* Miconia albicans Triana...
  
   & Planch.) Copel.
• Eriosorus wurdackii A. Tryon

xEriosonia hybrids

• xEriosonia incognita L.D. Gomez (Eriosorus warscewiczii x Jamesonia alstonii)
• xEriosonia kupperi (I. Losch) Pic.Serm.
• xEriosonia longifolia (Baker
  Baker
  A baker is someone who bakes and sells bread, Cakes and similar foods may also be produced, as the traditional boundaries between what is produced by a baker as opposed to a pastry chef have blurred in recent decades...
  
  ) Pic.Serm.
• xEriosonia .D. Gomez (Eriosorus warscewiczii x Jamesonia rotundifolia)
• "xEriosonia elongatus" (Eriosorus x elongatus (Grev. & Hook.) Copel.; not yet described as an xEriosonia (Eriosorus cheilanthoides x Jamesonia sp.)

External links

• World species of Jamesonia: http://homepages.caverock.net.nz/~bj/fern/jamesonia.htm
• USDA Plants Profile for Eriosorus: USDA Plants Profile
• World species of Eriosorus: http://homepages.caverock.net.nz/~bj/fern/eriosorus.htm