What is "erica tetralix"

Heather \Heath"er\ (h[e^][th]"[~e]r; 277. This is the only pronunciation in Scotland), n. [See Heath.] Heath. [Scot.]

Gorse and grass And heather, where his footsteps pass, The brighter seem.
--Longfellow.

Heather bell (Bot.), one of the pretty subglobose flowers of two European kinds of heather ( Erica Tetralix, and Erica cinerea).

Erica tetralix (cross-leaved heath) is a species of flowering plant in the family Ericaceae, 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. In bogs, wet heaths and damp coniferous woodland, E. tetralix can become a dominant part of the flora. It has also been introduced to parts of North America.