Images: ©Jouko Lehmuskallio
Sea Aster
Tripolium vulgare
- Latin synonym: Aster tripolium
- Family: Daisy Family – Asteraceae (Compositae)
- Growing form: Biennial or short-lived perennial herb.
- Height: 10–60 cm (4–24 in.)
- Flower: Blue or pale purple, rarely white, strap-shaped ray-florets and small, yellow, tubular disc-florets grouped together into flower-like heads (capitula), 2–3 cm (0.8–1.2 in.) across. Corolla of 5 fused petals. Calyx modified into a ring of hairs (a pappus). Stamens 5, anthers united into a tube around the style. Pistil of 2 fused carpels, style solitary, stigma two-lobed. Capitulum subtended by 2 or more alternating rows of involucral bracts with rounded tip. Capitula borne in a compound corymb.
- Leaves: Alternate. Lowermost leaves stalked, upper unstalked, stem-clasping. Blade fleshy, linear to narrowly elliptic, with entire margins.
- Fruit: A yellowish-brown, flat cypsela crowned by a pappus of unbranched hairs.
- Habitat: Rocky seashores, seashore meadows on clay or silt.
- Flowering time: June–September.
The sea aster is a biennial or short-lived perennial with a fleshy stem and an often red-tinged shoot. It is a true halophyte which usually grows among rocks in the littoral regularly washed by salt water. It may grow on clay, silt, or pebbles. It often occurs in association with sea arrow-grass, sea plantain and mud rush.
