Erica (plant)


Erica is a genus of roughly 858 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. The genus Calluna was formerly included in Erica; it differs in having even smaller scale-leaves, and the flower corolla consisting of separate petals. Erica is sometimes referred to as "winter heather" to distinguish it from Calluna "summer heather". Erica are commonly mistaken for Tulipa pulchella and Tulipa saxatilis due to a mistranslation in the song Erika.

European species

Most European species are dwarf shrubs, growing 20–80 cm tall. The largest are the tree heather and the broom heather, which can reach 6–10 meters.

African species

The majority of the more than 750 African heather species occur in the fynbos of the Cape region of South Africa, where they grow alongside Protea species and other shrubs. Most South African species have long, disc-shaped flowers. In the Afromontane zones of East Africa, heather species that grow to several meters tall, such as Erica arborea and Erica rossii grow.

Description

Most of the species of Erica are small shrubs from high, though some are taller; the tallest are E. arborea and E. scoparia, both of which can reach up to tall. All are evergreen, with minute, needle-like leaves long. Flowers are sometimes axillary, and sometimes borne in terminal umbels or spikes, and are usually outward or downward facing. The seeds are very small, and in some species may survive in the soil for decades.

Taxonomy

Dulfer published the last revision of the genus Erica in the 1960s, treating 605 species. Many new species have subsequently been described and a further 83 have been included in Erica from former "minor genera", such as Phillipia Klotzsch and Blaeria L. A more recent overview of Erica species is provided in an electronic identification aid, but a modern taxonomic revision of the genus as a whole is still lacking.

Phylogeny

A number of increasingly detailed phylogenetic hypotheses for Erica have been published based on nuclear ribosomal and plastid DNA sequences. The closest relatives of Erica are Daboecia and Calluna, representing the oldest surviving lineages of a, by inference, ancestrally Palearctic tribe Ericeae. The small number of European Erica species represent the oldest lineages of the genus, within which a single, order-of-magnitude more species-rich, African clade is nested. Within the African clade, Cape and Madagascan/Mascarene species respectively represent monophyletic groups.

Species

Selected species include:

Etymology

The Latin word erica means "heath" or "broom". It is believed that Pliny adapted erica from Ancient Greek ἐρείκη. The expected Traditional [English pronunciation of Latin|Anglo-Latin] pronunciation,, may be given in dictionaries, but is more commonly heard.

Distribution and habitat

Around 690 of the species are endemic to South Africa, and these are often called the Cape heaths, forming the largest genus in the fynbos. The remaining species are native to other parts of Africa, Madagascar, the Mediterranean, and Europe.
Like most Ericaceae, Erica species are mainly calcifuges, being limited to acidic or very acidic soils. In fact, the term "ericaceous" is frequently applied to all calcifuges, and to the compost used in their cultivation. Soils range from dry, sandy soils to extremely wet ones such as bog. They often dominate dwarf-shrub habitats, or the ground vegetation of open acidic woodland.

Ecology

Plants of this genus are eaten mainly by the larvae of many Lepidoptera species, including Saturnia pavonia, garden tiger moth, true lover's knot, wormwood pug, the silver-studded blue, and the Coleophora case-bearers C. juncicolella and C. pyrrhulipennella.
Some species of sunbirds are known to visit and pollinate Erica. Two such species are the southern double-collared sunbird and the orange-breasted sunbird.

Cultivation

Erica species are grown as landscape or garden plants for their floral effect. They associate well with conifers and are frequently seen in planting schemes as massed ground cover beneath varieties of dwarf conifers. They are capable of producing flower colour throughout the year. They can also be grown in tubs or window boxes to provide interest through autumn and into winter.
The cultivation of larger beds of heath rather than individual plants became more popular in the 1920s, after gardeners began to try and replicate natural heathland environments in their gardens.