Erica tetralix, the cross-leaved heath, is a species of flowering plant in the family Ericaceae, native to western Europe.
It is a perennial subshrub with glandular leaves in whorls of four (whence the name). Appearing in summer and autumn, small pink bell-shaped flowers droop in compact clusters at the ends of the shoots.
Related species E. cinerea has glabrous leaves in whorls of three. Calluna vulgaris has much smaller and scale-like leaves in opposite and decussate pairs.[1]
The sticky, adhesive glands on leaves, sepals and other parts of the plant prompted Charles Darwin to suggest that this species might be a protocarnivorous plant, but little, if any, research has been done on this.[2]
E. tetralix is native to western Europe from southern Portugal to central Norway, as well as a number of boggy regions further from the coast in Central Europe such as Austria and Switzerland. It has also been introduced to parts of North America.
E. tetralix can become a dominant part of the flora in bogs, wet heaths, and damp coniferous woodland.[3]
A species of Trialeurodes whitefly discovered in 1971 was named T. ericae for the plant, due to its frequent association with it.[4]
In cultivation, like other heathers, E. tetralix requires an acidic soil, as it is a calcifuge. Numerous cultivars have been developed for garden use, of which E. tetralix f. alba 'Alba Mollis'[5] (a white-flowered variety) and E. tetralix f. stellata 'Pink Star'[6] have gained the Royal Horticultural Society's Award of Garden Merit.[7]
It appears in the 1938 German marching song "Erika" by Herms Niel.
