The 4 stamps with first day postmarks are from 2010 Know 10 Trees issue aiming to raise public's awareness of Singapore's most common roadside trees.
The trees on the stamps are (from left to right):Rain Tree,Tembusu,Sea Apple and Trumpet Tree.
Rain Tree (Samanea saman) is a species of flowering tree in the pea family, Fabaceae, that is native to the Neotropics. Its range extends from Mexico south to Peru and Brazil, but it has been widely introduced to South and Southeast Asia, as well as the Pacific Islands, including Hawaii.
The Tembusu (Fagraea fragrans) is a large evergreen tree native to South-east Asia. Its trunk is dark brown, with deeply fissured bark, looking somewhat like a bittergourd. It grows in an irregular shape from 10 to 25m high . Its leaves are light green and oval in shape. Its yellowish flowers have a distinct fragrance and the fruits of the tree are bitter tasting red berries, which are eaten by birds and fruit bats.
Sea Apple(Syzygium grande) is a flowering plant that belongs to the myrtle family, Myrtaceae. The genus comprises about 1100 species, and has a native range that extends from Africa and Madagascar through southern Asia east through the Pacific. Its highest levels of diversity occur from Malaysia to northeastern Australia, where many species are very poorly known and many more have not been described taxonomically.
Trumpet Tree (Tabebuia rosea) is one of 100 species in the tribe Tecomeae of the family Bignoniaceae. The species range from northern Mexico and southern Florida south to northern Argentina.