''Mertensia'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial no ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek language, Greek words ('container, vessel') and ('seed'), and refers to ...

s in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...

Boraginaceae. They are

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...

herbaceous plant Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...

s with blue or sometimes white flowers that open from pink-tinged buds. Such a change in flower color is common in

Boraginaceae Boraginaceae, the borage or forget-me-not family, includes about 2,000 species of shrubs, trees and herbs in 146, to 156 genera with a worldwide distribution. The APG IV system from 2016 classifies the Boraginaceae as single family of the ord ...

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 In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

, the flowers are usually salverform (trumpet-shaped) rather than campanulate (bell-shaped). ''Mertensia'' is

native Native may refer to: People * Jus soli, citizenship by right of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Native Americans (disambiguation) In arts and entertai ...

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 A center of origin is a geographical area where a group of organisms, either domesticated or wild, first developed its distinctive properties. They are also considered centers of diversity. Centers of origin were first identified in 1924 by N ...

is in the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico ...

. ''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 Maritime may refer to: Geography * Maritime Alps, a mountain range in the southwestern part of the Alps * Maritime Region, a region in Togo * Maritime Southeast Asia * The Maritimes, the Canadian provinces of Nova Scotia, New Brunswick, and Prin ...

plant of

Arctic The Arctic ( or ) is a polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada ( Yukon, Northwest Territories, Nunavut), Danish Realm ( Greenland), Finland, Icel ...

and

subarctic The subarctic zone is a region in the Northern Hemisphere immediately south of the true Arctic, north of humid continental regions and covering much of Alaska, Canada, Iceland, the north of Scandinavia, Siberia, and the Cairngorms. Generally ...

coastlines, and ''Mertensia virginica'', which is found from the

Appalachian Mountains The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a mountain range, system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovicia ...

west to Minnesota, Iowa, and Missouri. Most of the

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate ...

are

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

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 Naturalization (or naturalisation) is the legal act or process by which a non-citizen of a country may acquire citizenship or nationality of that country. It may be done automatically by a statute, i.e., without any effort on the part of the i ...

in Europe. About 12 other species are known in cultivation.

Anthony Huxley Anthony Julian Huxley (2 December 1920 – 26 December 1992) was a British botanist. He edited '' Amateur Gardening'' from 1967 to 1971, and was vice-president of the Royal Horticultural Society in 1991. He was the son of Julian Huxley. He wa ...

, 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 Inuit (; iu, ᐃᓄᐃᑦ 'the people', singular: Inuk, , dual: Inuuk, ) are a group of culturally similar indigenous peoples inhabiting the Arctic and subarctic regions of Greenland, Labrador, Quebec, Nunavut, the Northwest Territories, ...

ate the

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow h ...

s 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 name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

s have been

published Publishing is the activity of making information, literature, music, software and other content available to the public for sale or for free. Traditionally, the term refers to the creation and distribution of printed works, such as books, newsp ...

in ''Mertensia''.''Mertensia'' in

Tropicos Tropicos is an online botanical database containing taxonomic information on plants, mainly from the Neotropical realm ( Central, and South America South America is a continent entirely in the Western Hemisphere and mostly in the S ...

(See ''External links'' below). Most authors have recognized about 45 species, but in 2014, the authors of a

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

study recommended the acceptance of at least 62.

Species

Author citations are from

or the

International Plant Names Index The International Plant Names Index (IPNI) describes itself as "a database of the names and associated basic bibliographical details of seed plants, ferns and lycophytes." Coverage of plant names is best at the rank of species and genus. It inclu ...

.''Mertensia'' in

. (see ''External links'' below).

Classification

''Mertensia'' is a member of the

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. This definition is contested, in part due to conf ...

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 In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

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 Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived c ...

analysis of

DNA sequence DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. The ...

Taxonomy

The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

for ''Mertensia'' is ''M. virginica''.''Mertensia'' In: Index Nominum Genericorum. In:

Regnum Vegetabile The International Association for Plant Taxonomy (IAPT) is an organization established to promote an understanding of plant biodiversity, facilitate international communication of research between botanists, and oversee matters of uniformity and ...

(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 Sakhalin ( rus, Сахали́н, r=Sakhalín, p=səxɐˈlʲin; ja, 樺太 ''Karafuto''; zh, c=, p=Kùyèdǎo, s=库页岛, t=庫頁島; Manchu: ᠰᠠᡥᠠᠯᡳᠶᠠᠨ, ''Sahaliyan''; Orok: Бугата на̄, ''Bugata nā''; Nivkh: ...

and the

Kuril Islands The Kuril Islands or Kurile Islands (; rus, Кури́льские острова́, r=Kuril'skiye ostrova, p=kʊˈrʲilʲskʲɪjə ɐstrɐˈva; Japanese: or ) are a volcanic archipelago currently administered as part of Sakhalin Oblast in the ...

.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 Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film) ...

''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 In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic grou ...

group consisting of three

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

s 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 ' (Latin for "The Species of Plants") is a book by Carl Linnaeus, originally published in 1753, which lists every species of plant known at the time, classified into genera. It is the first work to consistently apply binomial names and was the ...

'', Swedish botanist

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...

placed five species in the genus ''

Pulmonaria ''Pulmonaria'' (lungwort) is a genus of flowering plants in the family Boraginaceae, native to Europe and western Asia, with one species (''P. mollissima'') east to central Asia. According to various estimates there may be between 10 and 18 spe ...

''.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 Albrecht Wilhelm Roth (6 January 1757 – 16 October 1834) was a physician and botanist born in Dötlingen, Germany. He studied medicine at the Universities of Halle and Erlangen, where he received his doctorate in 1778. After graduation, he p ...

, 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 Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualist ...

gland In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream ( endocrine gland) or into cavities inside the body or its outer surface ( exocrine gland). Structure ...

s 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 A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

that has been a source of confusion ever since. ''Mertensia'' was named after the German

botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek w ...

Franz Carl Mertens Franz Carl Mertens (3 April 1764 – 19 June 1831) was a German botanist who was a native of Bielefeld. He specialized in the field of phycology. Mertens studied theology and languages at the University of Halle, and after graduation tau ...

.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 George Don (29 April 1798 – 25 February 1856) was a Scottish botanist and plant collector. Life and career George Don was born at Doo Hillock, Forfar, Angus, Scotland on 29 April 1798 to Caroline Clementina Stuart and George Don (b.1756), ...

, 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 (November 18, 1810 – January 30, 1888) is considered the most important American botanist of the 19th century. His '' Darwiniana'' was considered an important explanation of how religion and science were not necessarily mutually exc ...

,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 (July 6, 1860 – July 25, 1931) was a Swedish-born, American botanist who was the first curator of the New York Botanical Garden Herbarium. Biography Per Axel Rydberg was born in Odh, Västergötland, Sweden and emigrated to t ...

,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 The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal areas ...

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 A monograph is a specialist work of writing (in contrast to reference works) or exhibition on a single subject or an aspect of a subject, often by a single author or artist, and usually on a scholarly subject. In library cataloging, ''monogra ...

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 In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analysis of DNA data has shown that many of the species are

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

, 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 Rank is the relative position, value, worth, complexity, power, importance, authority, level, etc. of a person or object within a ranking, such as: Level or position in a hierarchical organization * Academic rank * Diplomatic rank * Hierarchy * ...

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 Sample or samples may refer to: Base meaning * Sample (statistics), a subset of a population – complete data set * Sample (signal), a digital discrete sample of a continuous analog signal * Sample (material), a specimen or small quantity of s ...

so far.

Evolution

In the earlier infrageneric classifications of ''Mertensia'', some of the groups were based on shared "primitive"

characters Character or Characters may refer to: Arts, entertainment, and media Literature * ''Character'' (novel), a 1936 Dutch novel by Ferdinand Bordewijk * ''Characters'' (Theophrastus), a classical Greek set of character sketches attributed to The ...

rather than the derived character states that show true phylogenetic relationships. In ''Mertensia'', as elsewhere, such groups have often proved to be

paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In ...

. 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

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

s (> 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 The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular ...

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 Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametoph ...

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

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s of ''Mertensia''. A

molecular clock The molecular clock is a figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. The biomolecular data used for such calculations are usually nucle ...

analysis has estimated that ''Mertensia'' diverged from ''Asperugo'' in the late

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but t ...

or early

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent ...

. ''Asperugo'' and ''Mertensia'' do not closely resemble each other morphologically. Being mostly plants of

subarctic climate The subarctic climate (also called subpolar climate, or boreal climate) is a climate with long, cold (often very cold) winters, and short, warm to cool summers. It is found on large landmasses, often away from the moderating effects of an ocean, ge ...

s, ''Mertensia'' spread southward and to lower elevation during periods of

Pleistocene The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed i ...

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate bet ...

, then retreated northward and to higher elevation during

interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene ...

s. ''Mertensia'' originated in Asia and dispersed over the

Beringia Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72 degrees north latitude in the Chukchi Sea; and on the south by the tip o ...

land bridge In biogeography, a land bridge is an isthmus or wider land connection between otherwise separate areas, over which animals and plants are able to cross and colonize new lands. A land bridge can be created by marine regression, in which sea l ...

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

Biodiversity Heritage Library The Biodiversity Heritage Library (BHL) is the world’s largest open access digital library for biodiversity literature and archives. BHL operates as worldwide consortiumof natural history, botanical, research, and national libraries working toge ...

): :
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
:
page 318page 372volume 4A general history of the dichlamydeous plantsDon, George, 1798-1856authorsBHL
:
page 179page 199volume 2, part 1View BookSynoptical flora of North America:Gray, Asa, 1810-1888authorsBHL
:
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
At:List of families
At:Families and Genera in GRIN
At:Queries
At:GRIN taxonomy for plants

''Mertensia''BoraginaceaeBoraginaleslamiidsasteridsEmbryophytaStreptophytinaStreptophytaViridiplantaeEukaryotaTaxonomyUniProt

''Mertensia''BoraginaceaeBoraginaleslamiidsasteridsEmbryophytaStreptophytinaStreptophytaViridiplantaeEukaryotaTaxonomy BrowserTaxonomy DatabaseTaxonomyNCBI
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''Mertensia''BoraginaceaeBoraginalesMagnoliopsidaTracheophytaPlantsGlobal Species

''Mertensia''BoraginaceaeAngiospermsBrowseThe Plant List
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''Mertensia''

USDA Plants Profile
* * {{Taxonbar, from=Q765547 Boraginaceae genera Flora of North America