Ericales

The order includes 22 families, according to the APG IV system of classification.

The Ericales include trees, bushes, lianas, and herbaceous plants. Together with ordinary autophytic plants, they include chlorophyll-deficient mycoheterotrophic plants (e.g., Sarcodes sanguinea) and carnivorous plants (e.g., genus Sarracenia). Mycorrhizal associations are quite common among the order representatives, and three kinds of mycorrhiza are found exclusively among Ericales (namely, ericoid, arbutoid and monotropoid mycorrhiza). In addition, some families among the order are notable for their exceptional ability to accumulate aluminum.

Many species have five petals, often grown together. Fusion of the petals as a trait was traditionally used to place the order in the subclass Sympetalae.

Ericales are a cosmopolitan order. Areas of distribution of families vary largely – while some are restricted to tropics, others exist mainly in Arctic or temperate regions. The entire order contains over 8,000 species, of which the Ericaceae account for 2,000–4,000 species (by various estimates).

According to molecular studies, the lineage that led to Ericales diverged from other plants about 127 million years or diversified 110 million years ago.

Economic importance

The most commercially used plant in the order is tea (Camellia sinensis) from the family Theaceae. The order also includes some edible fruits, including kiwifruit (esp. Actinidia chinensis var. deliciosa), persimmon (genus Diospyros), blueberry, huckleberry, cranberry, Brazil nut, and Mamey sapote. The order also includes shea (Vitellaria paradoxa), which is the major dietary lipid source for millions of sub-Saharan Africans. Many Ericales species are cultivated for their showy flowers: well-known examples are azalea, Rhododendron, Camellia, heather, Primula, Cyclamen, Phlox, and busy Lizzie.