1, Flowering shoot of _Erica cinerea_, about 1-1/2 nat. size. 2, Flower cut lengthwise. 3, Stamen showing appendages and porous dehiscence of anther. 4, Capsule showing the loculicidal dehiscence; a few seeds remain attached to the central axis. 5, Diagram of the flower having four sepals, four divisions of the corolla, eight stamens in two rows, and four divisions of the pistil.] The order falls into four distinct tribes, which are characterized by the relative position of the ovary and by the fruit and seed. They are as follows:-- 1. _Rhododendron tribe_, characterized by capsular fruit, seed with a loose coat, deciduous petals and anthers without appendages. It consists mainly of the great genus _Rhododendron_ (in which _Azalea_ is included by recent botanists), which is chiefly developed in the mountains of eastern Asia, many species occurring on the Himalayas. _Dabeocia_, St Dabeoc's heath, occurs in Ireland. 2. _Arbutus Tribe._--Fruit a berry or capsule, petals deciduous and anthers with bristle-like appendages, chiefly north temperate to arctic in distribution. _Arbutus Unedo_, the strawberry-tree, so called from its large scarlet berry, is a southern European species which extends into south Ireland. _Arctostaphylos_ (bearberry) and _Andromeda_ are arctic and alpine genera occurring in Britain. _Epigaea repens_ is the trailing arbutus or mayflower of Atlantic America. 3. _Vaccinium Tribe._--Ovary inferior, fruit a berry. Extends from the north temperate zone to the mountains of the tropics. _Vaccinium_, the largest genus, has four British species: _V. Myrtillus_ is the bilberry (q.v.), blaeberry or whortleberry, _V. Vitis-Idaea_ the cowberry, and _V. Oxycoccos_ the cranberry (q.v.). This tribe is sometimes regarded as a separate order Vacciniaceae, distinguished by its inferior ovary. 4. _Erica Tribe._--Fruit usually a capsule, seeds round, not winged; corolla persisting round the ripe fruit; anthers often appendaged. The largest genus is _Erica_, the true heath (q.v.), with over 400 species, the great majority of which are confined to the Cape; others occur on the mountains of tropical Africa and in Europe and North Africa, especially the Mediterranean region. _E. cinerea_ (purple heather) and _E. Tetralix_ (cross-leaved heath) are common British heaths. _Calluna_ is the ling or Scotch heather.