TheEricaceae (/ˌɛrɪˈkeɪsi.aɪ,-iː/) are afamily offlowering plants, commonly known as theheath orheather family, found most commonly in acidic and infertile growing conditions. The family is large, with about 4,250 known species spread across 124 genera,[2] making it the 14th most species-rich family of flowering plants.[3] The many well known and economically important members of the Ericaceae include thecranberry,blueberry,huckleberry,rhododendron (includingazaleas), and various common heaths and heathers (Erica,Cassiope,Daboecia, andCalluna for example).[4]
Michel Adanson used the term Vaccinia to describe a similar family, butAntoine Laurent de Jussieu first used the term Ericaceae. The name comes from the type genusErica, which appears to be derived from the Greek wordereíkē (ἐρείκη). 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 beforeLinnaean times, and simply been formalised when Linnaeus describedErica in 1753, and then again when Jussieu described the Ericaceae in 1789.[8]
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).[9] Within tribe Rhodoreae, five genera were described,Rhododendron L. (includingAzalea L. pro parte),Therorhodion Small,Ledum L.,Tsusiophyllum Max.,Menziesia J. E. Smith, that were eventually transferred intoRhododendron, along with Diplarche from the monogeneric tribe Diplarcheae.[10]
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 aphylogenetic framework.[11] 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 4,000 species:[3]
The family is largely composed of plants that can tolerate acidic, infertile, shady conditions.[13] Due to their tolerance of acidic conditions, this plant family is also typical of peatbogs and blanket bogs; examples includeRhododendron groenlandicum and species in the genusKalmia.[14] In easternNorth America, members of this family often grow in association with anoak canopy, in a habitat known as anoak-heath forest.[15] Plants in Ericaceae, especially species inVaccinium, rely onbuzz pollination for successful pollination to occur.[16]
The majority of ornamental species fromRhododendron are native toEast Asia, but most varieties cultivated today are hybrids.[17][18] Most rhododendrons grown in the United States are cultivated in thePacific Northwest. The United States is the top producer of both blueberries and cranberries, with the state of Maine growing the majority oflowbush blueberry.[19][20][21] The wide distribution of genera within Ericaceae has led to situations in which distinct American and European plants share the same common name, e.g. blueberry (Vaccinium corymbosum in North America andV.myrtillus in Europe) and cranberry (V.macrocarpon in America andV.oxycoccos in Europe).
Like other stress-tolerant plants, many Ericaceae havemycorrhizal fungi to assist with extracting nutrients from infertilesoils, as well as evergreen foliage to conserve absorbed nutrients.[22] This trait is not found in theClethraceae andCyrillaceae, the two families most closely related to the Ericaceae. Most Ericaceae (excluding the Monotropoideae, and some Epacridoideae) form a distinctive accumulation ofmycorrhizae, in which fungi grow in and around the roots and provide the plant with nutrients. ThePyroloideae aremixotrophic and gain sugars from the mycorrhizae, as well as nutrients.[23]
The cultivation of blueberries, cranberries, andwintergreen for their fruit and oils relies especially on these unique relationships with fungi, as a healthy mycorrhizal network in the soil helps the plants to resist environmental stresses that might otherwise damage crop yield.[24] Ericoid mycorrhizae are responsible for a high rate of uptake of nitrogen, which causes naturally low levels of free nitrogen in ericoid soils.[25] These mycorrhizal fungi may also increase the tolerance of Ericaceae toheavy metals in soil, and may cause plants to grow faster by producingphytohormones.[26]
In many parts of the world, a "heath" or "heathland" is an environment characterised by an open dwarf-shrub community found on low-quality acidic soils, generally dominated by plants in Ericaceae. Heathlands are a broadly anthropogenic habitat, requiring regular grazing or burning to prevent succession.[27] Heaths are particularly abundant – and constitute important cultural elements – in Norway, the United Kingdom, the Netherlands, Germany, Spain, Portugal, and other countries in Central and Western Europe.[28] The most common examples of plants in Ericaceae which dominate heathlands areCalluna vulgaris,Erica cineria,Erica tetralix, andVaccinium myrtillus.[29][30]
Some evidence suggestseutrophic rainwater can convert ericoid heaths with species such asErica tetralix tograsslands.Nitrogen is particularly suspect in this regard, and may be causing measurable changes to the distribution and abundance of some ericaceous species.[25]
^abStevens, P.F. (2001 onwards). "Ericaceae".Angiosperm Phylogeny Website. Retrieved 29 December 2014.
^Kron, Kathleen A.; Powell, E. Ann & Luteyn, J.L. (2002). "Phylogenetic relationships within the blueberry tribe (Vaccinieae, Ericaceae) based on sequence data from MATK and nuclear ribosomal ITS regions, with comments on the placement ofSatyria".American Journal of Botany.89 (2):327–336.doi:10.3732/ajb.89.2.327.PMID21669741.
^Patterson, Patricia A. (1985).Field Guide to the Forest Plants of Northern Idaho. United States Department of Agriculture Forest Service. pp. 37–47.
^Watson, L. & Dallwitz, M.J. (19 August 2014)."Ericaceae Juss".The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Retrieved30 December 2014.
^Loidi, Javier; de Blust, Geert; Campos, Juan Antonio; Haveman, Rense; Janssen, John (1 January 2020),"Heathlands of Temperate and Boreal Europe", in Goldstein, Michael I.; DellaSala, Dominick A. (eds.),Encyclopedia of the World's Biomes, Oxford: Elsevier, pp. 656–668,ISBN978-0-12-816097-8, retrieved4 December 2023
Stevens, P.F. (1971). "A classification of the Ericaceae: subfamilies and tribes".Botanical Journal of the Linnean Society.64 (1):1–53.doi:10.1111/j.1095-8339.1971.tb02133.x.
Cafferty, Steve; Jarvis, Charles E. (November 2002). "Typification of Linnaean Plant Names in Ericaceae".Taxon.51 (4):751–753.doi:10.2307/1555030.JSTOR1555030.
Stevens, P.F.; Luteyn, J.; Oliver, E.G.H.; Bell, T.L.; Brown, E.A.; Crowden, R.K.; George, A.S.; Jordan, G.J.; Ladd, P.; Lemson, K.; McLean, C.B.; Menadue, Y.; Pate, J.S.; Stace, H.M.; Weiller, C.M. (2004)."Ericaceae". In Kubitzki, K. (ed.).Flowering Plants. Dicotyledons: Celastrales, Oxalidales, Rosales, Cornales, Ericales. The families and genera of vascular plants. Vol. 6. Springer. pp. 145–194.ISBN9783540065128.
