Aster tripolium is a plant that is native to Europe. It is a member of the aster species, and is one of just two aster varieties that are native to the European continent. The aster tripolium is a perennial plant, and is typically found in marine settings or areas with a high salt content. Like many other members of the aster family, this plant is known for its purple daisy-like flowers. The aster tripolium is also known by its common name, the sea aster.
The sea aster is so named for its tendency to grow in coastal areas. It can be found in salt meadows, marshes, and islands. This plant can also thrive further inland in areas with unnaturally high salt concentrations, which may include highway roadsides or former mining sites. The aster tripolium grows along shores and coastlines, and can even grow directly out of a sea wall.
Different types of aster tripolium can be characterized as either rayed or rayless varieties. Rayless sea aster can survive in areas with very high salinity, while rayed version generally require lower salinity levels. The rayless versions of this plant either produce no flowers, or small versions of the blooms found on rayed sea asters. While rayed varieties typically produce blue or white flowers, rayless species are often associated with blooms that are yellow. Both of these plants have a very large central bud within the flower that is yellow or orange in color.
Aster tripolium produces flowers throughout the summer and fall. While this plant has a relatively short life in general, its flowers tend to last for a substantial portion of the plant's life. The flowers of the sea aster feature sharply pointed leaves that resemble the traditional daisy. The shape of these flowers help to give the plant its name, as the term aster comes from the Greek word for star. While the flowers of the rayed aster are relatively large and substantial, the blooms on the rayless varieties are looser and less full.
This plants tend to remain fairly small, and generally does not exceed 20 inches (50 cm) in height. The stems and leaves of the aster tripolium are yellowish-green in color, and the stem grows thicker as it extends towards the ground. Both the stem and leaves are often covered with a fine hair, giving the surface a rough texture. The leaves of the aster tripolium are thick and fleshy, which is due to the plant's tendency to store as much fresh water as possible to help it survive in salty environments.