“ The leaves are alternate, opposite or whorled in arrangement, and in their form and structure show well-marked adaptation for life in dry or exposed situations. Thus in the true heaths they are needle-like, with the margins often rolled back to form a groove or an almost closed chamber on the under side. In others such as Rhododendron or Arbutus they are often leathery and evergreen, the strongly cuticularized upper surface protecting a water-storing tissue situated above the green layers of the leaf. ”

“ 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. ”