The Ericaceae are a

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 ...

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, 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 the 14th most species-rich family of flowering plants. The many well known and economically important members of the Ericaceae include the

cranberry Cranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus ''Oxycoccus'' of the genus ''Vaccinium''. In Britain, cranberry may refer to the native species '' Vaccinium oxycoccos'', while in North America, cranberry ...

, blueberry,

huckleberry Huckleberry is a name used in North America for several plants in the family Ericaceae, in two closely related genera: ''Vaccinium'' and '' Gaylussacia''. The huckleberry is the state fruit of Idaho. Nomenclature The name 'huckleberry' is a Nor ...

rhododendron ''Rhododendron'' (; from Ancient Greek ''rhódon'' "rose" and ''déndron'' "tree") is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are nat ...

(including

azalea Azaleas are flowering shrubs in the genus ''Rhododendron'', particularly the former sections '' Tsutsusi'' (evergreen) and '' Pentanthera'' (deciduous). Azaleas bloom in the spring (April and May in the temperate Northern Hemisphere, and Octo ...

s), and various common heaths and heathers (''

Erica Erica or ERICA may refer to: * Erica (given name) * ''Erica'' (plant), a flowering plant genus * Erica (chatbot), a service of Bank of America * ''Erica'' (video game), a 2019 FMV video game * ''Erica'' (spider), a jumping spider genus * Eric ...

'', '' Cassiope'', ''

Daboecia ''Daboecia'' , or St. Dabeoc's heath, is a small genus of flowering plants in the family Ericaceae, containing two evergreen shrubs, closely related to the genus ''Erica''. They are native to cliffs and heathland in southern Atlantic Europe and t ...

'', and ''

Calluna ''Calluna vulgaris'', common heather, ling, or simply heather, is the sole species in the genus ''Calluna'' in the flowering plant family Ericaceae. It is a low-growing evergreen shrub growing to tall, or rarely to and taller, and is found wide ...

'' for example).

Description

The Ericaceae contain a morphologically diverse range of taxa, including

herb In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...

s, dwarf shrubs,

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from tree ...

s, and

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that ar ...

s. Their leaves are usually

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

, alternate or whorled, simple and without

stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...

s. Their flowers are

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have s ...

and show considerable variability. The

petal Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corolla''. Petals are usually ...

s are often fused (

sympetalous Sympetaly (fused petals) is a flower characteristic that historically was used to classify a grouping of plants termed Sympetalae, but this term has been abandoned in newer molecular based classifications, although the grouping has similarity to ...

) with shapes ranging from narrowly tubular to funnelform or widely urn-shaped. The corollas are usually radially symmetrical (

actinomorphic Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts. Uncommonly, flowers may have no axis of symmetry at all, typically because their parts are spirall ...

) and urn-shaped, but many flowers of the genus ''Rhododendron'' are somewhat bilaterally symmetrical (

zygomorphic Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts. Uncommonly, flowers may have no axis of symmetry at all, typically because their parts are spirall ...

). Anthers open by pores.

Taxonomy

Michel Adanson Michel Adanson (7 April 17273 August 1806) was an 18th-century French botanist and naturalist who traveled to Senegal to study flora and fauna. He proposed a "natural system" of taxonomy distinct from the binomial system forwarded by Linnaeus. ...

used the term Vaccinia to describe a similar family, but first used the term Ericaceae. The name comes from the type genus ''

'', which appears to be derived from the Greek word (). The exact meaning is difficult to interpret, but some sources show it as meaning 'heather'. The name may have been used informally to refer to the plants before Linnaean times, and simply been formalised when Linnaeus described ''Erica'' in 1753, and then again when Jussieu described the Ericaceae in 1789. Historically, the Ericaceae included both subfamilies and tribes. In 1971, Stevens, who outlined the history from 1876 and in some instances 1839, recognised six subfamilies (Rhododendroideae, Ericoideae, Vaccinioideae, Pyroloideae, Monotropoideae, and Wittsteinioideae), and further subdivided four of the subfamilies into tribes, the Rhododendroideae having seven tribes (Bejarieae, Rhodoreae, Cladothamneae, Epigaeae, Phyllodoceae, and Diplarcheae). Within tribe Rhodoreae, five genera were described, ''

Rhododendron ''Rhododendron'' (; from Ancient Greek ''rhódon'' "rose" and ''déndron'' "tree") is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are nat ...

'' L. (including ''Azalea'' L. pro parte), ''Therorhodion'' Small, '' Ledum'' L., ''Tsusiophyllum'' Max., '' Menziesia'' J. E. Smith, that were eventually transferred into ''Rhododendron'', along with Diplarche from the monogeneric tribe Diplarcheae. In 2002, systematic research resulted in the inclusion of the formerly recognised families Empetraceae, Epacridaceae, Monotropaceae, Prionotaceae, and Pyrolaceae into the Ericaceae based on a combination of molecular, morphological, anatomical, and embryological data, analysed within a

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 ...

framework. The move significantly increased the morphological and geographical range found within the group. One possible classification of the resulting family includes 9 subfamilies, 126 genera, and about 4000 species: * Enkianthoideae Kron, Judd & Anderberg (one genus, 16 species) * Pyroloideae Kosteltsky (4 genera, 40 species) * Monotropoideae Arnott (10 genera, 15 species) * Arbutoideae Niedenzu (up to six genera, about 80 species) * Cassiopoideae Kron & Judd (one genus, 12 species) * Ericoideae Link (19 genera, 1790 species) * Harrimanelloideae Kron & Judd (one species) * Epacridoideae Arn. (=Styphelioideae Sweet) (35 genera, 545 species) * Vaccinioideae Arnott (50 genera, 1580 species)

Genera

:See the full list at List of Ericaceae genera.

Distribution and ecology

The Ericaceae have a nearly worldwide distribution. They are absent from continental

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...

, parts of the high

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 ...

, central

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is ...

, northern and central Australia, and much of the lowland

tropics The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referre ...

and

neotropics The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In biog ...

. The family is largely composed of plants that can tolerate acidic, infertile conditions. Like other stress-tolerant plants, many Ericaceae have mycorrhizal

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

to assist with extracting nutrients from infertile

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

s, as well as evergreen foliage to conserve absorbed nutrients. This trait is not found in the Clethraceae and Cyrillaceae, the two families most closely related to the Ericaceae. Most Ericaceae (excluding the Monotropoideae, and some Epacridoideae) form a distinctive accumulation of

mycorrhizae A mycorrhiza (from Greek μύκης ', "fungus", and ῥίζα ', "root"; pl. mycorrhizae, mycorrhiza or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the pla ...

, in which fungi grow in and around the roots and provide the plant with nutrients. The Pyroloideae are mixotrophic and gain sugars from the mycorrhizae, as well as nutrients. In many parts of the world, a "

heath A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a cooler a ...

" or "heathland" is an environment characterised by an open dwarf-

community found on low-quality acidic soils, generally dominated by plants in the Ericaceae. A common example is ''

Erica tetralix ''Erica tetralix'', the cross-leaved heath, is a species of flowering plant in the family Ericaceae, native to western Europe, from southern Portugal to central Norway, as well as a number of boggy regions further from the coast in Central Europe ...

''. This plant family is also typical of peat

bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg ...

s and blanket bogs; examples include ''

Rhododendron groenlandicum ''Rhododendron groenlandicum'' (bog Labrador tea, muskeg tea, swamp tea, or in northern Canada, Hudson's Bay tea; formerly ''Ledum groenlandicum'' or ''Ledum latifolium'') is a flowering shrub with white flowers and evergreen leaves that is used ...

'' and '' Kalmia polifolia''. In eastern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the C ...

, members of this family often grow in association with an

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ...

canopy, in a habitat known as an oak-heath forest. In heathland, plants in the family Ericaceae serve as hostplants to the butterfly '' Plebejus argus''''.'' Some evidence suggests

eutrophic Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytoplan ...

rainwater can convert ericoid heaths with species such as ''Erica tetralix'' to

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge ( Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natu ...

Nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at sevent ...

is particularly suspect in this regard, and may be causing measurable changes to the distribution and abundance of some ericaceous species.

References

Bibliography