| Ericaceae | |
|---|---|
| Leptecophylla juniperina | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Asterids |
| Order: | Ericales |
| Family: | Ericaceae Juss. |
| Type genus | |
| Erica L. |
|
| Subfamilies | |
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The Ericaceae, commonly known as the heath or heather family, is a group of mostly calcifuge (lime-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.[1] There are many well-known and economically important members of the Ericaceae, these include the cranberry, blueberry, huckleberry, azalea, rhododendron, and various common heaths and heathers (Erica, Cassiope, Daboecia, and Calluna for example).[2]
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The Ericaceae contains a morphologically diverse range of taxa, including herbs, dwarf shrubs, shrubs and trees. The leaves are usually alternate or whorled, simple and without stipules, and hermaphrodite flowers. The flowers show considerable variability. The petals 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).[3]
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.[1]
The family is largely made up of calcifuge plants, that tend to thrive only in acidic soils. This is a trait not found in the Clethraceae and Cyrillaceae, the two families most closely related to the Ericaceae.
Most Ericaceae (excluding the Monotropoideae, Pyroloideae, and some Styphelioideae) form mycorrhizae, where fungi 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 edaphically stressful environments worldwide.[4] The Pyroleae tribe are mixotrophic and gain sugars from the mycorrhizae as well as nutrients.[5]
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 the Ericaceae. In eastern North America, members of this family often grow in association with an oak canopy, in a type of ecology known as an oak-heath forest. [6][7]
In 2002 systematic research conducted by Kron et al.[8] resulted in the inclusion of the formerly recognised families Empetraceae, Epacridaceae, Monotropaceae, Prionotaceae and Pyrolaceae 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:
The name Ericaceae comes from the type genus Erica, which appears derived from the Greek word "ereike". The exact meaning is difficult to interpret, but some sources show it as simply meaning "heather".[9] 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 Jussieu described the Ericaceae in 1789.[10]