RHS GENEALOGY FOR GARDENERS EUDICOTS sepals, free or fused at the base, and four or Ericaceae five petals, sometimes free, though usually The heather family fused together to form a tube, bell or urn. The stamens are in whorls of four or five and Hugely useful in the garden, this family of mainly woody plants includes the heathers the pollen is released from the anthers by (Calluna, Erica, Daboecia), azaleas, rhododendrons, wintergreens (Gaultheria), way of pores at the tips. Pieris and mountain laurels (Kalmia). Commercially significant crops include Fruit blueberries and cranberries (Vaccinium). Fruits are typically dry capsules, though fleshy Size Origins fruits, such as blueberries, are not uncommon. One of the larger families, the Ericaceae contains Earliest evidence of this family dates to the Late Leaves over 3,850 species. Within this great diversity are Cretaceous (about 90 million years ago). Fossils many small genera with one or two species, and suggest that Ericaceae was once more diverse in Most Ericaceae have evergreen, alternate leaves and Vaccinium corymbosum, three titans; Rhododendron (with 1,000 species), Europe, which was home to genera now restricted no stipules. Some species, such as many azaleas, highbush blueberry Erica (850 species) and Vaccinium (500 species). to Asia and/or America. are deciduous, while opposite and whorled leaf It should be noted that azaleas are included arrangements are also known. Leaf margins are within Rhododendron. Flowers entire, toothed or curled under, and some species USES FOR THIS FAMILY (including many rhododendrons) have dense hair Great floral diversity is encompassed by this or scales on the lower surfaces. Range This family is traditionally found in areas with family, so keep in mind that there are always nutrient-poor, acidic soils, such as heathlands Ericaceae is absent from Antarctica and from exceptions to the basic forms described here. (named after heather) and peat bogs. They survive most tropical lowland forest. It is common on Flowers usually include both male and female by binding their roots to fungal threads in the soil, creating a symbiotic relationship known as tropical mountains, in southern Africa and in the parts, are clustered in inflorescences, and are mycorrhiza. The fungus greatly improves the cooler parts of eastern North America somewhat pendulous. In Rhododendron, roots’ ability to extract soil nutrients and, in and eastern Asia. numerous (often sticky) bracts protect the return, the plant gives to the fungus sugars unopened flowers. There are four or five manufactured by photosynthesis. Most Ericaceae require acidic soils, so if your soil is alkaline they Tubular flower are unlikely to thrive. To get around this problem Flower in you can grow small species in containers using an section acidic compost named after the family (erica- ceous). If you’re not sure what kind of soil you have, buy a pH test kit or observe neighbouring gardens to see what thrives. Calluna vulgaris, ling heather The only member of the Rhododendron arboreum, genus Calluna, ling heather is Anther Ovary tree-like rhododendron Rhododendron a weed in New Zealand and The genusRhododendron is the largest in Ericaceae canescens, considered a potential weed and includes large trees like this, through to tiny mountain azalea in Australia. creeping alpine species, though most are shrubs. 178 179.