Sea aster

Tripolium pannonicum (sea aster, formerly Aster tripolium) is a salt-tolerant biennial or short-lived herbaceous perennial of the daisy family (Asteraceae), reaching up to about 50 cm tall from a fleshy taproot. The smooth, sometimes purplish, erect to ascending stem bears alternate, narrowly lance-shaped, fleshy and slightly succulent leaves with entire to weakly toothed margins, an adaptation to the saline halophytic habitats it occupies. From July through autumn the plant produces loose corymbose clusters of daisy-like flower heads about 1–2 cm across; two morphological forms occur, a typical rayed form with about a dozen long pale blue to lilac (occasionally white) ray florets surrounding a yellow disc, and a rayless form composed only of yellow disc florets. The fruit is a small flattened achene topped with a soft bristly pappus that aids wind dispersal. Native to Eurasia and northern Africa, sea aster is confined to coastal salt marshes, brackish estuaries, sea cliffs, and occasional inland salt works, and is a valuable late-season nectar source for migrating butterflies.