The
Ericaceae, commonly known as the
heath or
heather family, is a group of mostly
calcifugeA calcifuge is a plant that does not tolerate alkaline soil. The word is derived from the Latin 'to flee from chalk'. These plants are also described as ericaceous, as the prototypical calcifuge is the genus Erica...
(
limeCalcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
-hating) flowering plants. The family is large, with roughly 4000 species spread across 126 genera, making it the 14th most speciose family of flowering plants. There are many well-known and economically important members of the Ericaceae, these include the
cranberryCranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus Oxycoccus of the genus Vaccinium. In some methods of classification, Oxycoccus is regarded as a genus in its own right...
,
blueberryBlueberries are flowering plants of the genus Vaccinium with dark-blue berries and are perennial...
,
huckleberryHuckleberry is a common name used in North America for several species of plants in two closely related genera in the family Ericaceae:* Vaccinium* GaylussaciaHuckleberry may also refer to:-Plants:...
,
azaleaAzaleas are flowering shrubs comprising two of the eight subgenera of the genus Rhododendron, Pentanthera and Tsutsuji . Azaleas bloom in spring, their flowers often lasting several weeks...
,
rhododendronRhododendron is a genus of over 1 000 species of woody plants in the heath family, most with showy flowers...
, and various common heaths and heathers (
EricaErica ,the heaths or heathers, is a genus of approximately 860 species of flowering plants in the family Ericaceae. The English common names "heath" and "heather" are shared by some closely related genera of similar appearance....
,
CassiopeCassiope is a genus of 9-12 small shrubby species in the family Ericaceae. They are native to the Arctic and north temperate montane regions. Common names, shared with several other similar related genera, include heather and heath....
,
DaboeciaDaboecia is a small genus in the family Ericaceae, containing two shrubby species, closely related to the genus Erica.Daboecia differs from European Erica species in having a deciduous corolla which is substantially larger than the corolla in the same species of Erica. The leaves are always...
, and
CallunaCalluna vulgaris is the sole species in the genus Calluna in the family Ericaceae. It is a low-growing perennial shrub growing to tall, or rarely to and taller, and is found widely in Europe and Asia Minor on acidic soils in open sunny situations and in moderate shade...
for example).
Description
The Ericaceae contains a morphologically diverse range of taxa, including
herbA herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
s, dwarf shrubs,
shrubA shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s and
treeA tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s. The leaves are usually alternate or whorled, simple and without
stipuleIn botany, stipule is a term coined by Linnaeus which refers to outgrowths borne on either side of the base of a leafstalk...
s, and hermaphrodite flowers. The flowers show considerable variability. The
petalPetals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...
s are often fused (sympetalous) with shapes ranging from narrowly tubular to funnelform or widely bowl-shaped. The corollas are usually radially symmetrical (actinomorphic) but many flowers of the genus
Rhododendron are somewhat bilaterally symmetrical (zygomorphic).
Distribution and ecology
Ericads have a nearly worldwide distribution. They are absent from continental Antarctica, parts of the high Arctic, central Greenland, northern and central Australia, and much of the lowland tropics and neotropics.
The family is largely made up of
calcifugeA calcifuge is a plant that does not tolerate alkaline soil. The word is derived from the Latin 'to flee from chalk'. These plants are also described as ericaceous, as the prototypical calcifuge is the genus Erica...
plants, that tend to thrive only in
acidic soilThe soil pH is a measure of the acidity or basicity in soils. pH is defined as the negative logarithm of the activity of hydrogen ions in solution. It ranges from 0 to 14, with 7 being neutral. A pH below 7 is acidic and above 7 is basic. Soil pH is considered a master variable in soils as it...
s. This is a trait not found in the
ClethraceaeClethraceae is a small family of flowering plants in the order Ericales, native to warm temperate to tropical regions of Asia and the Americas, with one species also on Madeira...
and
CyrillaceaeCyrillaceae is a small family of flowering plants in the order Ericales, native to warm temperate to tropical regions of the Americas. The family comprises two genera, each with a single species, Cyrilla racemiflora and Cliftonia monophylla....
, the two families most closely related to the Ericaceae.
Most Ericaceae (excluding the Monotropoideae, Pyroloideae, and some Styphelioideae) form
mycorrhizaeEricoid mycorrhiza are a symbiotic relationship between fungi and the roots of plants from the order Ericales. Ericoid mycorrhiza are considered crucial for the success of the family Ericaceae in variety of edaphically stressful environments worldwide...
, where
fungiA fungus is a member of a large 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, Fungi, which is separate from plants, animals, and bacteria...
grow in and around the roots and provide the plant with nutrients. This symbiotic relationship is considered crucial to the success of members of the family in
edaphicEdaphic is a nature related to soil. Edaphic qualities may characterize the soil itself, including drainage, texture, or chemical properties such as pH. Edaphic may also characterize organisms, such as plant communities, where it specifies their relationships with soil...
ally stressful environments worldwide. The
PyroleaePyroleae is a tribe of plants in the Ericaceae family. It consists of four genera; Chimaphila containing 5 species, Pyrola containing 30 species and Moneses and Orthilia which are monotypic. They are mixotrophic, gaining nutrition from photosynthesis, but also from mycorrhizal fungi....
tribe are mixotrophic and gain sugars from the mycorrhizae as well as nutrients.
In many parts of the world, a "
heath-Habitats:* Heath or heathland, low-growing woody vegetation, mostly consisting of heathers and related species* Heaths in the British National Vegetation Classification system...
" 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. In eastern
North AmericaNorth America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, members of this family often grow in association with an
oakAn oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
canopy, in a type of ecology known as an oak-heath forest.
Systematics
In 2002 systematic research conducted by Kron
et al. resulted in the inclusion of the formerly recognised families Empetraceae, Epacridaceae,
MonotropaceaeMonotropaceae was a small family of flowering plants under the old Cronquist system of plant classification. It included 10 genera Allotropa, Cheilotheca, Hemitomes, Monotropa, Monotropastrum, Monotropsis, Pityopus, Pleuricospora, Pterospora, Sarcodes....
, Prionotaceae and
PyrolaceaePyrolaceae was a small family of flowering plants under the old Cronquist system of plant classification. It included the four genera Chimaphila, Moneses, Orthilia, and Pyrola, and sometimes also the eight genera formerly usually placed in the family Monotropaceae.Recent genetic research by the...
into the Ericaceae. This was based on a combination of molecular, morphological, anatomical, and embryological data, analysed within a phylogenetic framework. The move significantly increased the morphological and geographical range found within the group. The resulting family now includes 9 subfamilies, 126 genera, and c. 4000 species:
- Enkianthoideae
Enkianthus is a genus of shrubs or small trees in the heath family . Its native range is in Asia, as far west as the eastern Himalayas, as far south as Indochina, and as far north and east as China and Japan....
Kron, Judd & Anderberg (1 genus, 16 species)
- Pyroloideae Kosteltsky (4 genera, 40 species)
- Monotropoideae Arnott (10 genera, 15 species)
- Arbutoideae Niedenzu (5 genera, 80 species)
- Cassiopoideae
Cassiope is a genus of 9-12 small shrubby species in the family Ericaceae. They are native to the Arctic and north temperate montane regions. Common names, shared with several other similar related genera, include heather and heath....
Kron & Judd (1 genus, 12 species)
- Ericoideae Link (19 genera, 1790 species)
- Harrimanelloideae Kron & Judd (1 genus, 2 species)
- Styphelioideae Sweet (35 genera, 545 species)
- Vaccinioideae Arnott (50 genera, 1580 species)
Etymology
The name Ericaceae comes from the type genus
EricaErica ,the heaths or heathers, is a genus of approximately 860 species of flowering plants in the family Ericaceae. The English common names "heath" and "heather" are shared by some closely related genera of similar appearance....
, which appears derived from the Greek word "ereike". The exact meaning is difficult to interpret, but some sources show it as simply meaning "heather". The name may have been used informally to refer to the plants in pre-Linnaean times, and was simply formalised when Linnaeus described
Erica in 1753, and then when
JussieuAntoine Laurent de Jussieu was a French botanist, notable as the first to propose a natural classification of flowering plants; much of his system remains in use today.-Life:...
described the Ericaceae in 1789.
External links