What is (a) An herbaceous composite plant (Eupatorium purpureum), often having hollow stems, and bearing purplish flowers in small corymbed heads. (b) The sea trumpet called?

trumpetweed — (a) An herbaceous composite plant (Eupatorium purpureum), often having hollow stems, and bearing purplish flowers in small corymbed heads. (b) The sea trumpet. (Webster's 1913.)

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