The Boreal Kingdom or Holarctic Kingdom (Holarctis) is a floristic kingdom identified by botanist Ronald Good (and later by Armen Takhtajan), which includes the

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout ...

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, Iceland, N ...

portions of North America and

Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...

. Its

flora Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' ...

is inherited from the ancient

supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leav ...

of Laurasia. However, parts of the floristic kingdom (and most of its

Circumboreal Region The Circumboreal Region in phytogeography is a floristic region within the Holarctic Kingdom in Eurasia and North America, as delineated by such geobotanists as Josias Braun-Blanquet and Armen Takhtajan. It is the largest floristic region i ...

) were glaciated during the

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 in ...

and as a consequence have a very young flora. Cenozoic

relict A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...

s found refuge in the southern and mountainous parts of the kingdom, especially in the Eastern Asiatic Region and southern

North American Atlantic Region North American Atlantic Region is a floristic region within the Holarctic Kingdom identified by Armen Takhtajan and Robert F. Thorne, spanning from the Atlantic and Gulf coasts to the Great Plains and comprising a major part of the United States ...

. Good noted that many plant species of temperate North America and Eurasia were very closely related, despite their separation by the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

and the Bering Strait. Millions of years ago, before the opening of the Atlantic Ocean, North America and Eurasia were joined as a single continent, Laurasia. After the opening of the Atlantic, the continents were connected to one another periodically via land bridges linking

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...

and

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive region, geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a ...

. Until a few million years ago, the global

climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologi ...

was warmer than at present, especially at higher latitudes, and many temperate climate species were distributed across North America and Eurasia via Alaska and Siberia. The sharply cooler climate of the past few million years eliminated a temperate-zone connection between North America and Eurasia, but common Laurasian origins and a long history of temperate-climate land bridges account for the botanical similarities between the temperate floras on the two continents. A floristic kingdom is the botanical analogue to an

biogeographic realm A biogeographic realm or ecozone is the broadest biogeographic division of Earth's land surface, based on distributional patterns of terrestrial organisms. They are subdivided into bioregions, which are further subdivided into ecoregions. De ...

, which takes into account the distribution of animal as well as plant species. Many biogeographers distinguish the Boreal Kingdom as comprising two realms, the

Nearctic The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America ...

(North America) and Palearctic (North Africa and Eurasia). Others, based on the distribution of related plant and animal families, include the Palearctic and Nearctic in a single

Holarctic The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical reg ...

realm, which corresponds to Good's Boreal Kingdom. __NOTOC__

Flora

According to Takhtajan (1978), the following families are endemic to this kingdom:

Ginkgoaceae The Ginkgoaceae is a family of gymnosperms which appeared during the Mesozoic Era, of which the only extant representative is ''Ginkgo biloba'', which is for this reason sometimes regarded as a living fossil A living fossil is an extant tax ...

, Cephalotaxaceae,

Glaucidiaceae Ranunculaceae (buttercup or crowfoot family; Latin "little frog", from "frog") is a family of over 2,000 known species of flowering plants in 43 genera, distributed worldwide. The largest genera are ''Ranunculus'' (600 species), ''Delphinium' ...

, Hydrastidaceae ('' Hydrastis''),

Trochodendraceae Trochodendraceae is the only family of flowering plants in the order Trochodendrales. It comprises two extant genera, each with a single species along with up to five additional extinct genera and a number of extinct species. The living speci ...

, Tetracentraceae, Cercidiphyllaceae, Euptelaceae (''

Euptelea ''Euptelea'' is a genus of two species of flowering plants in the monogeneric family Eupteleaceae. The genus is found from Assam east through China to Japan, and consists of shrubs or small trees: *'' Euptelea pleiosperma'' *'' Euptelea polya ...

''),

Platanaceae Platanaceae, the "plane-tree family", is a family of flowering plants in the order Proteales. The family consists of only a single extant genus ''Platanus'', with eight known species. The plants are tall trees, native to temperate and subtropic ...

, Eucommiaceae, Rhoipteleaceae, Leitneriaceae,

Paeoniaceae The peony or paeony is a flowering plant in the genus ''Paeonia'' , the only genus in the family Paeoniaceae . Peonies are native to Asia, Europe and Western North America. Scientists differ on the number of species that can be distinguished, ...

Crossosomataceae Crossosomataceae is a small plant family, consisting of four genera of shrubs found only in the dry parts of the American southwest and Mexico. This family has included up to ten species in the past, although as of 2021 six species are still ...

, Stachyuraceae, Fouquieriaceae, Diapensiaceae,

Simmondsiaceae Simmondsiaceae or the jojoba family is a family of flowering plants. The family is not recognized by all taxonomic systems, the single species, ''Simmondsia chinensis'', often being treated as belonging to family Buxaceae. The APG II system, of ...

, Pterostemonaceae,

Penthoraceae ''Penthorum'' is a genus of plants in the order Saxifragales. They are erect herbaceous perennials about half a meter tall. The genus consists of two species, one from east Asia and one from eastern North America. It is variously classified i ...

, Bretschneideraceae, Limnanthaceae, Davidiaceae ('' Davidia''), Toricelliaceae,

Helwingiaceae The genus ''Helwingia'' consists of shrubs or rarely small trees native to eastern Asia, the Himalayas, and northern Indochina. It is the only genus in the family Helwingiaceae. Description The plants have alternate, evergreen or deciduous leave ...

, Theligonaceae, Dipentodontaceae,

Cynomoriaceae ''Cynomorium'' is a genus of parasitic perennial flowering plants in the family Cynomoriaceae. The genus consists of only one species, ''Cynomorium coccineum'' (although one of its subspecies is sometimes treated as a separate species). Its plac ...

Adoxaceae Adoxaceae, commonly known as moschatel family, is a small family of flowering plants in the order Dipsacales, now consisting of five genera and about 150–200 species. They are characterised by opposite toothed leaves, small five- or, more rare ...

, Trapellaceae (''Trapella''), Butomaceae, Scheuchzeriaceae, Aphyllanthaceae.Takhtajan, A. (1986). ''Floristic Regions of the World''. (translated by T.J. Crovello & A. Cronquist). University of California Press, Berkeley

According to the same author, the following families are well represented:

Magnoliaceae The Magnoliaceae () are a flowering plant family, the magnolia family, in the order Magnoliales. It consists of two genera: ''Magnolia'' and '' Liriodendron'' (tulip trees). Unlike most angiosperms, whose flower parts are in whorls (rings), t ...

, Lauraceae,

Ranunculaceae Ranunculaceae (buttercup or crowfoot family; Latin "little frog", from "frog") is a family of over 2,000 known species of flowering plants in 43 genera, distributed worldwide. The largest genera are ''Ranunculus'' (600 species), ''Delphinium' ...

Berberidaceae The Berberidaceae are a family of 18 genera of flowering plants commonly called the barberry family. This family is in the order Ranunculales. The family contains about 700 known species, of which the majority are in ''Berberis''. The species ...

Hamamelidaceae Hamamelidaceae, commonly referred to as the witch-hazel family, is a family of flowering plants in the order Saxifragales. The clade consists of shrubs and small trees positioned within the woody clade of the core Saxifragales. An earlier syste ...

, Fagaceae,

Betulaceae Betulaceae, the birch family, includes six genera of deciduous nut-bearing trees and shrubs, including the birches, alders, hazels, hornbeams, hazel-hornbeam, and hop-hornbeams numbering a total of 167 species. They are mostly natives of the ...

Juglandaceae The Juglandaceae are a plant family known as the walnut family. They are trees, or sometimes shrubs, in the order Fagales. Members of this family are native to the Americas, Eurasia, and Southeast Asia. The nine or ten genera in the family have ...

Caryophyllaceae Caryophyllaceae, commonly called the pink family or carnation family, is a family of flowering plants. It is included in the dicotyledon order Caryophyllales in the APG III system, alongside 33 other families, including Amaranthaceae, Cactacea ...

Chenopodiaceae Amaranthaceae is a family of flowering plants commonly known as the amaranth family, in reference to its type genus '' Amaranthus''. It includes the former goosefoot family Chenopodiaceae and contains about 165 genera and 2,040 species, making i ...

Polygonaceae The Polygonaceae are a family of flowering plants known informally as the knotweed family or smartweed—buckwheat family in the United States. The name is based on the genus '' Polygonum'', and was first used by Antoine Laurent de Jussieu in 1 ...

Plumbaginaceae Plumbaginaceae is a family of flowering plants, with a cosmopolitan distribution. The family is sometimes referred to as the leadwort family or the plumbago family. Most species in this family are perennial herbaceous plants, but a few grow ...

Theaceae Theaceae (), the tea family, is a family of flowering plants comprising shrubs and trees, including the economically important tea plant, and the ornamental camellias. It can be described as having from seven to 40 genera, depending on the sour ...

Salicaceae The Salicaceae is the willow family of flowering plants. The traditional family (Salicaceae ''sensu stricto'') included the willows, poplar, aspen, and cottonwoods. Genetic studies summarized by the Angiosperm Phylogeny Group (APG) have greatly ...

Brassicaceae Brassicaceae () or (the older) Cruciferae () is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous plants, while some are shrubs. The leav ...

Ericaceae The Ericaceae are a family of flowering plants, commonly known as the heath or heather family, found most commonly in acidic and infertile growing conditions. The family is large, with c.4250 known species spread across 124 genera, making it th ...

Primulaceae The Primulaceae , commonly known as the primrose family (but not related to the evening primrose family), are a family of herbaceous and woody flowering plants including some favourite garden plants and wildflowers. Most are perennial though som ...

Malvaceae Malvaceae, or the mallows, is a family of flowering plants estimated to contain 244 genera with 4225 known species. Well-known members of economic importance include okra, cotton, cacao and durian. There are also some genera containing familiar ...

Euphorbiaceae Euphorbiaceae, the spurge family, is a large family of flowering plants. In English, they are also commonly called euphorbias, which is also the name of a genus in the family. Most spurges, such as '' Euphorbia paralias'', are herbs, but some, ...

Thymelaeaceae The Thymelaeaceae are a cosmopolitan family of flowering plants composed of 50 genera (listed below) and 898 species.Zachary S. Rogers (2009 onwards)A World Checklist of Thymelaeaceae (version 1) Missouri Botanical Garden Website, St. Louis. It ...

, Rosaceae, Fabaceae,

Cornaceae The Cornaceae are a cosmopolitan family of flowering plants in the order Cornales. The family contains approximately 85 species in two genera, ''Alangium'' and ''Cornus''. They are mostly trees and shrubs, which may be deciduous or evergreen, alt ...

Araliaceae The Araliaceae are a family of flowering plants composed of about 43 genera and around 1500 species consisting of primarily woody plants and some herbaceous plants. The morphology of Araliaceae varies widely, but it is predominantly distinguish ...

Apiaceae Apiaceae or Umbelliferae is a family of mostly aromatic flowering plants named after the type genus '' Apium'' and commonly known as the celery, carrot or parsley family, or simply as umbellifers. It is the 16th-largest family of flowering plan ...

, Rhamnaceae,

Gentianaceae Gentianaceae is a family of flowering plants of 103 genera and about 1600 species. Etymology The family takes its name from the genus '' Gentiana'', named after the Illyrian king Gentius. Distribution Distribution is cosmopolitan. Characteri ...

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 or ...

Scrophulariaceae The Scrophulariaceae are a family of flowering plants, commonly known as the figwort family. The plants are annual and perennial herbs, as well as shrubs. Flowers have bilateral (zygomorphic) or rarely radial (actinomorphic) symmetry. The Scr ...

, Lamiaceae,

Campanulaceae The family Campanulaceae (also bellflower family), of the order Asterales, contains nearly 2400 species in 84 genera of herbaceous plants, shrubs, and rarely small trees, often with milky sap. Among them are several familiar garden plants belo ...

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

Liliaceae The lily family, Liliaceae, consists of about 15 genera and 610 species of flowering plants within the order Liliales. They are monocotyledonous, perennial, herbaceous, often bulbous geophytes. Plants in this family have evolved with a fair a ...

Iridaceae Iridaceae is a family of plants in order Asparagales, taking its name from the irises, meaning rainbow, referring to its many colours. There are 66 accepted genera with a total of c. 2244 species worldwide (Christenhusz & Byng 2016). It include ...

Orchidaceae Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

Juncaceae Juncaceae is a family of flowering plants, commonly known as the rush family. It consists of 8 genera and about 464 known species of slow-growing, rhizomatous, herbaceous monocotyledonous plants that may superficially resemble grasses and s ...

, Cyperaceae, Poaceae,

Pinaceae The Pinaceae, or pine family, are conifer trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, larches, pines and spruces. The family is included in the order Pinales, formerly kn ...

, Cupressaceae,

Aspleniaceae The Aspleniaceae (spleenworts) are a family of ferns, included in the order Polypodiales. The composition and classification of the family have been subject to considerable changes. In particular, there is a narrow circumscription, Aspleniaceae ...

, Polypodiaceae.

Subdivisions

The kingdom is subdivided into three floristic subkingdoms and nine

floristic regions A phytochorion, in phytogeography, is a geographic area with a relatively uniform composition of plant species. Adjacent phytochoria do not usually have a sharp boundary, but rather a soft one, a transitional area in which many species from both r ...

Boreal Subkingdom

* Eastern Asiatic Region *

* Rocky Mountain Region

Tethyan Subkingdom

* Macaronesian Region *

Mediterranean Region In biogeography, the Mediterranean Basin (; also known as the Mediterranean Region or sometimes Mediterranea) is the region of lands around the Mediterranean Sea that have mostly a Mediterranean climate, with mild to cool, rainy winters and wa ...

* Saharo-Arabian Region * Irano-Turanian Region

Madrean Floristic Region

Madrean Region The Madrean Region (named after the Sierra Madre Occidental) is a floristic region within the Holarctic Kingdom in North America, as delineated by Armen Takhtajan and Robert F. Thorne. It occupies arid or semiarid areas in the southwestern Unite ...

References

{{floristic regions Floristic kingdoms Holarctic flora