Gaultheria Kalm ex L. (1753), in the family Ericaceae, contains 134 species of mainly juicy-fruited shrubs.

Description Trees to 8m, but usually shrubs, the bark and leaves often aromatic. The leaves are alternate, evergreen, often sharp-pointed. The flowers are solitary or in spikes in the leaf axils, occasionally unisexual. Sepals 5, joined at the base, usually becoming fleshy in fruit; petals 5, equal, joined to form a bell-shaped corolla. Stamens usually 10, the anthers often with appendages, opening by pores. Ovary superior. Carpels 5, fused, with numerous ovules; style short and straight. Pollination is by insects. The fruits are usually capsules surrounded by a fleshy calyx, but often the capsule itself is fleshy. Seeds small and numerous.

Key Recognition Features The fleshy calyx of most species is easily recognised; in some southern-hemisphere species, however, the calyx is not fleshy, but the fruit itself is berry-like.

Evolution and Relationships Many of the species in which the calyx is not fleshy, such as G. mucronata (L. fil.) Hook. & Arn., were formerly put in the genus Pernettya. Subsequently, species were found that had a slightly fleshy calyx and a fleshy capsule, so the distinction between the two was considered worthless. Hybrids between the 2 groups, such as G. x wisleyensis, previously called Gaulnettya, have a fleshy calyx partially surrounding a berry.

Ecology and Geography In rocky woods, in bogs, and on open hillsides. Most species are found in Malaysia, eastern Asia, Australia and New Zealand, and Central and South America. Five, including G. shallon Pursh and G. procumbens L., are found in North America.
Comment Gaultheria procumbens, the checkerberry or creeping wintergreen, and G. shallon contain oil of wintergreen, of which the active ingredient is methyl salicylate. The berries of G. insana (Molina) Middleton are poisonous. Gaultheria mucronata, formerly called Pernettya mucronata, from southern Chile and Argentina, is often planted for its berries, which may be white, pink, red, or purple, and are abundant if 1 male plant is grown for every 5 or 6 females.