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. Idea ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of ...

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, cranber ...

, 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 Nort ...

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 nativ ...

(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 Oct ...

s), and various common heaths and heathers ('' Erica'', '' Cassiope'', '' Daboecia'', 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 wi ...

'' 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 medicina ...

s, dwarf shrubs, shrubs, 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 are ...

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 ...

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 usuall ...

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) 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 spiral ...

). 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 '' Erica'', 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 nativ ...

'' L. (including ''Azalea'' L. pro parte), ''Therorhodion'' Small, ''

Ledum ''Ledum'' was a genus in the family Ericaceae, including 8 species of evergreen shrubs native to cool temperate and subarctic regions of the Northern Hemisphere and commonly known as Labrador tea. It is now recognised as a subsection of section R ...

'' L., ''Tsusiophyllum'' Max., ''

Menziesia ''Menziesia'' was a genus of flowering plant in the family Ericaceae. More recently it has been reclassified within the genus '' Rhododendron''. it was formally transferred in 2011. Species * ''Menziesia ciliicalyx'' (Miq.) Maxim. = '' Rhododend ...

'' 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 Monotropoideae, sometimes referred to as monotropes, are a flowering plant subfamily in the family Ericaceae. Members of this subfamily are notable for their mycoheterotrophic and non-photosynthesizing or achlorophyllous characteristics. Descri ...

Arnott (10 genera, 15 species) *

Arbutoideae The Arbutoideae are a subfamily in the plant family Ericaceae. Phylogenetic analysis supported all genera of the subfamily as monophyletic, except '' Arbutus''. Moreover, it was suggested that the non-sister relationship between Mediterranean and ...

Niedenzu (up to six genera, about 80 species) *

Cassiopoideae Cascade, Smallsat and Ionospheric Polar Explorer (CASSIOPE), is a Canadian Space Agency (CSA) multi-mission satellite operated by the University of Calgary. The mission development and operations from launch to February 2018 was funded through CS ...

Kron & Judd (one genus, 12 species) * Ericoideae Link (19 genera, 1790 species) * Harrimanelloideae Kron & Judd (one species) *

Epacridoideae Epacridoideae is a subfamily of the family Ericaceae. The name Styphelioideae Sweet is also used. The subfamily contains around 35 genera and 545 species. Many species are found in Australasia, others occurring northwards through the Pacific to So ...

Arn. (=Styphelioideae Sweet) (35 genera, 545 species) * Vaccinioideae Arnott (50 genera, 1580 species)

Genera

:See the full list at

List of Ericaceae genera This is a list of genera in the plant family Ericaceae, which includes the heaths, heathers, epacrids, and blueberries. As currently circumscribed, the family contains about 4000 species into more than 120 genera classified into 9 subfamilies. C ...

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 co ...

, 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, Iceland ...

, 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 referred ...

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 bi ...

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

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 plan ...

, 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 ...

" or "heathland" is an environment characterised by an open dwarf- shrub community found on low-quality acidic soils, generally dominated by plants in the Ericaceae. A common example is '' Erica tetralix''. 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; a ...

s and blanket bogs; examples include '' Rhododendron groenlandicum'' and ''

Kalmia polifolia ''Kalmia polifolia'', previously known as ''Kalmia glauca'' and commonly called bog laurel, swamp laurel, or pale laurel, is a perennial evergreen shrub of cold acidic bogs, in the family Ericaceae. It is native to north-eastern North America, f ...

''. In eastern North America, members of this family often grow in association with an oak 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 The silver-studded blue (''Plebejus argus'') is a butterfly in the family Lycaenidae. It has bright blue wings rimmed in black with white edges and silver spots on its hindwings, lending it the name of the silver-studded blue. ''P. argus'' can ...

''''.'' 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 phytoplank ...

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 natur ...

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 seve ...

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

References

Bibliography