Erica tetralix (Cross-leaved Heath)

Plant of the week
Picture of Erica tetralix (Cross-leaved Heath)
Erica tetralix (Cross-leaved Heath)

Heaths are one of the important habitats in Sussex. In contrast to the chalky Downs, these are places with acidic soils and consequently a quite different suite of plants. Over 85% of lowland heath has been lost since 1800. While this is a lot, matters are even worse than the figures suggest because what remains is fragmented, isolating the various populations of flora and fauna that depend on such habitats.

Picture of Erica tetralix (Cross-leaved Heath)
Erica tetralix (Cross-leaved Heath)

This week’s #SxPOTW is Erica tetralix (Cross-leaved Heath), which is found in damper areas of heathland. It flowers slightly earlier than the other common heathland plant with ‘bell-shaped’ flowers, Erica cinerea (Bell Heather), which has much darker purple flowers.

Picture of Erica cinerea (Bell Heather)
Erica cinerea (Bell Heather)

The other classic plant of heathland is what many simply call ‘heather’ and others ‘ling’: Calluna vulgaris. This has quite different flowers that are only just emerging and will last through into September.

Picture of Calluna vulgaris (Heather)
Calluna vulgaris (Heather)

The distribution of the two Erica species is very similar across the county, whereas Calluna vulgaris is more widespread. Besides the pale pink flowers held in small terminal clusters, the tiny leaves are arranged in fours around the stem, giving it its specific name. These are covered in glandular sticky hairs, unlike Erica cinerea which has glabrous leaves arranged in threes. The very sticky nature of the plant led Charles Darwin to speculate that the plant might be ‘protocarnivorous’.

Distribution map of Erica tetralix (Cross-leaved Heath) in Sussex
Distribution of Erica tetralix (Cross-leaved Heath) in Sussex

Native. Sx: locally common. Wet heath and valley bogs. Still frequent on the Lower Greensand and in the St Leonard’s Forest area in WSx, and on Ashdown Forest and elsewhere in ESx, but has decreased since recording for Hall (1980). There are fewer recent records from St Leonard’s Forest and some other areas: populations have doubtless been lost to building development, forestry, drainage and other agricultural improvement. In addition, on neglected heathland there can be a build-up of dead vegetation which increases the severity of fires. The re-growth on ungrazed wet heathland tends to be dominated by Molinia, and species such as E. tetralix become scarcer. Erica tetralix is a ‘constant species’ of the Erica tetralix–Sphagnum compactum wet heath, of which the Sx heaths form an important part of the UK series.

Source: E. tetralix L. Cross-leaved Heath, The Flora of Sussex (2018)

There don’t appear to be any particular medicinal uses for the plant, although a yellow dye can be prepared from it and, in common with other heaths, besoms can be made from the pliable woody stems.

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