Mertensia

''Mertensia'' is a genus of flowering plants in the family Boraginaceae. They are perennial herbaceous plants with blue or sometimes white flowers that open from pink-tinged buds. Such a change in flower color is common in Boraginaceae and is caused by an increase of pH in the flower tissue. ''Mertensia'' is one of several plants that are commonly called "bluebell". In spite of their common name, the flowers are usually salverform (trumpet-shaped) rather than campanulate (bell-shaped).

''Mertensia'' is native to most of North America and to a large part of Asia from western China to northeastern Russia.Mare Nazaire, Xiao-Quan Wang, and Larry Hufford. 2014. "Geographic origins and patterns of radiation of ''Mertensia'' (Boraginaceae)". ''American Journal of Botany'' 101(1):104-118. . Its center of diversity is in the Rocky Mountains. ''Mertensia'' is mostly restricted to alpine, subalpine, and montane habitats.Mare Nazaira and Larry Hufford. 2014. "Phylogenetic Systematics of the Genus ''Mertensia'' (Boraginaceae)". ''Systematic Botany'' 39(1):268-303. . Notable exceptions are ''Mertensia maritima'', a maritime plant of Arctic and subarctic coastlines, and ''Mertensia virginica'', which is found from the Appalachian Mountains west to Minnesota, Iowa, and Missouri. Most of the species are endemic to very small areas of the Rocky Mountains.

''Mertensia virginica'' has the largest flowers in the genus and is commonly cultivated. It is sparingly naturalized in Europe. About 12 other species are known in cultivation.Anthony Huxley, Mark Griffiths, and Margot Levy (1992). ''The New Royal Horticultural Society Dictionary of Gardening''. The Macmillan Press,Limited: London. The Stockton Press: New York. (set). The Inuit ate the rhizomes of ''Mertensia maritima''.David J. Mabberley. 2008. ''Mabberley's Plant-Book'' third edition (2008). Cambridge University Press: UK. (see ''External links'' below).

Many of the species of ''Mertensia'' are hard to distinguish and some are possibly cryptic. Around 150 species names have been published in ''Mertensia''.''Mertensia'' in Tropicos (See ''External links'' below). Most authors have recognized about 45 species, but in 2014, the authors of a molecular phylogenetic study recommended the acceptance of at least 62.

Species

Author citations are from Tropicos or the International Plant Names Index.''Mertensia'' in International Plant Names Index. (see ''External links'' below).

Classification

''Mertensia'' is a member of the tribe Cynoglosseae.James I. Cohen. 2014. "A phylogenetic analysis of morphological and molecular characters of Boraginaceae: evolutionary relationships, taxonomy, and patterns of character evolution". ''Cladistics'' 30(2):139-169. Its closest relative is the monotypic Eurasian genus '' Asperugo''. These two are probably close to '' Anoplocaryum'', a genus of Central Asia and Siberia. The relationships of ''Anoplocaryum'' have never been investigated by cladistic analysis of DNA sequences.

Taxonomy

The type species for ''Mertensia'' is ''M. virginica''.''Mertensia'' In: Index Nominum Genericorum. In: Regnum Vegetabile (see ''External links'' below). ''Mertensia'' is divided into two sections: Stenhammaria and Mertensia. Section Stenhammaria consists of the circumboreal ''M. maritima'' and 11 of the 12 species from Asia.

The Central Asian species, ''M. dschagastanica'', is assigned to section Stenhammaria, but it is morphologically unusual and might constitute a third section of ''Mertensia''. It has never been sampled for DNA.

Section Mertensia consists of all of the North American species plus ''M. rivularis'', a denizen of the Russian half of the Beringian floristic region.

The North American species ''M. pilosa'' has been reported from Sakhalin and the Kuril Islands.Mikhail G. Popov. 1953. "Boraginaceae". pages 67-691 and 701-716. In: Boris K. Schischkin (editor). ''Flora of the USSR'', volume 19 - Tubiflorae. Izdatel'stvo Akademii Nauk SSSR: Moskva, Leningrad,, Russia. (published by the Academy of Sciences of the USSR).Rose Lavoott (translator). 1974. "Boraginaceae". pages 73-508 and 516-531. In: English translation of: Boris K. Schischkin (editor). ''Flora of the USSR'', volume 19 - Tubiflorae. Keter Press: Jerusalem, Israel. For: Israel Program for Scientific Translations. It is the only species of ''Mertensia'' that is native to both Asia and North America. It resembles ''M. rivularis'' and might be closer to that species than to the other species of North America. It also resembles ''M. platyphylla'' and some authors have placed it in synonymy under ''Mertensia platyphylla'' variety ''platyphylla''. It has not yet been sampled in a molecular phylogenetic study.

With the possible exception of ''M. pilosa'', North American ''Mertensia'' is a monophyletic group consisting of three clades that are known informally as the Pacific Northwest clade, the Southern Rocky Mountain clade, and the Central Rocky Mountain clade. These groups are named for the region where most of their species occur, but each includes species from well outside of that region.

History

In 1753, in his landmark '' Species Plantarum'', Swedish botanist Carl Linnaeus placed five species in the genus ''Pulmonaria''.Carolus Linnaeus (Carl von Linné). 1753. ''Species Plantarum'', 1st edition, 1:135-136. Holmiae: Impensis Laurentii Salvii (Lars Salvius). (A facsimile with an introduction by William T. Stearn was published by the Ray Society in 1957). (See ''External links'' below). Albrecht Wilhelm Roth, in 1797, separated what are now ''M. virginica'', ''M. maritima'', and ''M. sibirica'' from ''Pulmonaria'' to form the genus ''Mertensia'', based on their smaller and differently structured calyx, their different anther position, and the presence of nectar glands on the inner surface of the corolla.Albrecht Wilhelm Roth. 1797. "Mertensia". ''Catalecta Botanica'' 1:34-35. (See ''External links'' below). Roth described one species as ''Mertensia pulmonarioides'', apparently unaware that Linnaeus had already described it as ''Pulmonaria virginica''.James S. Pringle. 2004. "Nomenclature of the Virginia-bluebell, ''Mertensia virginica'' (Boraginaceae)". SIDA, contributions to botany 21(2):771-775.(see ''External links'' below) He thus created a superfluous synonym that has been a source of confusion ever since.

''Mertensia'' was named after the German botanist, Franz Carl Mertens.Umberto Quattrocchi. 2000. ''CRC World Dictionary of Plant Names'', volume III. CRC Press: Baton Rouge, New York, London, Washington DC. (vol. III). (see ''External links'' below).

In the time since ''Mertensia'' was erected in 1797, it has been the subject of six major revisions. These, in chronological order, were done by George Don (George Don, the younger (G. Don), not George Don, the elder (Don)),George Don (G.Don). 1838. "A general history of the dichlamydeous plants comprising complete descriptions of the different orders". volume 4 (Corolliflorae): ''Mertensia''. pages 318-320, 372. Gilbert and Rivington: London, UK. (see ''External links'' below). Asa Gray,Asa Gray. 1886. ''Synoptical Flora of North America'', volume 2, part 1 (Gamopetalae after Compositae): "Boraginaceae": pages 177-207. ''Mertensia'': pages 179, 199-201. Ivison, Blakeman, Taylor, and Company: New York, NY, USA. (see ''External links'' below). James Francis Macbride,James Francis Macbride. 1916. "The true mertensias of western North America". ''Contributions from the Gray Herbarium. New Series'' 48:1-20. (see ''External links'' below). Per Axel Rydberg,Per Axel Rydberg. 1922. ''Flora of the Rocky Mountains and Adjacent Plains'', 2nd edition. ''Mertensia''. pages 730-736. reprinted in 1954 by Hafner Publishing Company: New York, NY, USA. (see ''External links'' below). Louis Otho Williams,Louis Otho Williams. 1937. "A monograph of the genus ''Mertensia'' in North America". ''Annals of the Missouri Botanical Garden'' 24 (1):17-159. (see ''External links'' below). and Mikhail Grigorevich Popov.

Asa Gray divided ''Mertensia'' into two sections: Stenhammaria and Mertensia.Asa Gray. 1874. "Notes on Borraginaceae" (sic). ''Proceedings of the American Academy of Arts and Sciences'' 10(New Series volume 2):48-62. (see ''External links'' below). The section Stenhammaria was named for the Swedish naturalist and clergyman Christian Stenhammar, who is best known for his work in lichenology. Gray defined the section Stenhammaria as consisting only of the littoral species ''M. maritima'', but in 2014, it was expanded to comprise 12 species.

In 1886, Asa Gray described seven species in ''Mertensia''. After Gray completed his monograph of ''Mertensia'', many species were discovered by botanical expeditions in the western United States. Many of the species recognized by Macbride and Rydberg were later placed in synonymy by Louis O. Williams in his treatment of North American ''Mertensia'' in which he accepted only 24 species, far fewer than Macbride and Rydberg. ''M. pilosa'' was not mentioned anywhere in the monograph by Williams, not even as a synonym. Popov (1953) recognized the same 24 North American species as Williams as well as 14 species from Asia, including ''M. pilosa''. Phylogenetic analysis of DNA data has shown that many of the species are polyphyletic, but no comprehensive revision of the Asian or of the North American species has been attempted since 1953.

In 1967, one of the sections delineated by Popov was raised to the rank of genus as '' Pseudomertensia''.Harald Udo von Riedl. 1967. ''Pseudomertensia''. pages 58-63. In: "Boraginaceae". pages 1-281. In: Karl Heinz Rechinger (editor). ''Flora Iranica'', monograph 48. Akademische Druck- und Verlagsanstalt: Graz, Austria. This reclassification has been confirmed by molecular phylogenies which place ''Pseudomertensia'' closer to ''Myosotis'' than any of the genera that have been sampled so far.

Evolution

In the earlier infrageneric classifications of ''Mertensia'', some of the groups were based on shared "primitive" characters rather than the derived character states that show true phylogenetic relationships. In ''Mertensia'', as elsewhere, such groups have often proved to be paraphyletic. More recently, molecular phylogenetics has greatly clarified the ancestral and derived character states in ''Mertensia''. Some of the traits evolving later have appeared independently as many as seven times.

Ancestral states in ''Mertensia'' include short plant height (< 40 cm), long stamens (> 1.5 mm), filaments inserted higher in the corolla, calyces divided at least ²⁄₃ of the way to the base, and acute to acuminate calyx lobe apices. Their derived alternatives are greater plant height (> 40 cm), short stamens (< 1.5 mm), filaments attached lower in the corolla, and calyces divided less than halfway to the base, and obtuse calyx lobe apices.

The nutlets and pollen of ''Mertensia'' are nearly uniform and consequently, are not of much taxonomic value.Tomoko Fukuda and Hiroshi Ikeda. 2012. "Palynological analysis and taxonomic position of the genus ''Mertensia'' (Boraginaceae)". ''Botany'' 90(8):722-730. .

There are no known fossils of ''Mertensia''. A molecular clock analysis has estimated that ''Mertensia'' diverged from ''Asperugo'' in the late Oligocene or early Miocene. ''Asperugo'' and ''Mertensia'' do not closely resemble each other morphologically. Being mostly plants of subarctic climates, ''Mertensia'' spread southward and to lower elevation during periods of Pleistocene glaciation, then retreated northward and to higher elevation during interglacials. ''Mertensia'' originated in Asia and dispersed over the Beringian land bridge to North America. Most of the groups that originated in Asia are more diverse there,Sandy P. Harrison, G. Yu, H. Takahara, and Iain Colin Prentice. 2001. "Diversity of temperate plants in East Asia". ''Nature'' 413(6852):129-130.Robert E. Ricklefs, Hong Qian, and Peter S. White. 2004. "The region effect on mesoscale plant species richness between eastern Asia and eastern North America". ''Ecography'' 27(2):129-136. but ''Mertensia'' is a conspicuous exception in having most of its species in North America.

Gallery

Mertensia alpina (7977046090).jpg, Alpine bluebells ('' Mertensia alpina'')
Mertensiaarizonica.jpg, Aspen Bluebells (''Mertensia arizonica'')
Mertensia brevistyla TPrendusi lg.jpg, Short-styled Bluebell ('' Mertensia brevistyla'')Teresa Prendusi
Short-styled Bluebell (Mertensia brevistyla)
/ref>
Shot of blue mountain bluebells flowers hanging from a stem mertensia ciliata.jpg, Mountain bell ('' Mertensia ciliata'')
Mertensia franciscana1.jpg, Franciscan bluebells ('' Mertensia franciscana'')
Mertensia lanceolata NPS-1.jpg, Prairie bluebells ('' Mertensia lanceolata'')
Mertensia longiflora 1718.JPG, Long bluebells ('' Mertensia longiflora'')
Mertensia maritima (3701701247).jpg, Oysterplant (''Mertensia maritima'')
Mertensia oblongifolia flowers (3525613924).jpg, Oblongleaf bluebells ('' Mertensia oblongifolia'')
Tall Bluebells (3816794344).jpg, Tall bluebells ('' Mertensia paniculata'')
Virginia Bluebells at Rocky River.jpg, Virginia bluebells ('' Mertensia virginica '')

References

External links

Mabberley's Plant-book

''Mertensia'' (Search)
And''Mertensia'' (Search Exact)
At:Names
At:Tropicos
At:Science and Conservation
At:Missouri Botanical Garden

''Mertensia''Plant NamesIPNI

''Mertensia''Index Nominum GenericorumResearch and CollectionsSmithsonian National Museum of Natural History

page 34page 35''Catalecta Botanica''HathiTrust

CRC World Dictionary of Plant Names: M-Q
At:Botany & Plant Science
At:Life Science
At:CRC Press
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BHL
( Biodiversity Heritage Library):
:
page 135page 136''Species Plantarum'', 1st ed. (1753)
At:View Record of title 25
At:Titles by Carl von Linné (1707-1778)AuthorsBHL

Nomenclature of the Virginia bluebellVolume 21, View BookSIDA, contributions to botanyBHL
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page 318page 372volume 4A general history of the dichlamydeous plantsDon, George, 1798-1856authorsBHL
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page 179page 199volume 2, part 1View BookSynoptical flora of North America:Gray, Asa, 1810-1888authorsBHL
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Louis Otho Williams 1937volume 24Annals of the Missouri Botanical GardentitlesBHL
:
Asa Gray 1874volume 10 (New Series volume 2)Proceedings of the American Academy of Arts and SciencestitlesBHL

James Francis Macbride 1916

Per Axel Rydberg 1922Internet Archive

''Mertensia''
At:Species Records for ''Mertensia''
At:''Mertensia''
At:List of genera
At:Boraginaceae
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At:Families and Genera in GRIN
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At:GRIN taxonomy for plants

''Mertensia''BoraginaceaeBoraginaleslamiidsasteridsEmbryophytaStreptophytinaStreptophytaViridiplantaeEukaryotaTaxonomyUniProt

''Mertensia''BoraginaceaeBoraginaleslamiidsasteridsEmbryophytaStreptophytinaStreptophytaViridiplantaeEukaryotaTaxonomy BrowserTaxonomy DatabaseTaxonomyNCBI
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''Mertensia''

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Boraginaceae genera
Flora of North America