Europa 2011 stamps from Azerbaijan

The Azermarka has issued a series of two stamps to commemorate the "Forests" theme of this year Europa stamp issue. The stamps feature an Elm Tree and an Eastern plane tree.

The Elm tree (Ulmus) is deciduous and semi-deciduous tree. Elms first appeared in the Miocene period about 40 million years ago. During the 19th and early 20th centuries, many species and cultivars were planted as ornamentals in Europe, North America, and parts of the Southern Hemisphere. Elm leaves are alternate, with simple, single- or doubly serrate margins, usually asymmetric at the base and acuminate at the apex. The genus is hermaphroditic, having apetalous perfect flowers which are mostly wind-pollinated, although bees do visit them. The fruit is a round wind-dispersed samara flushed with chlorophyll, facilitating photosynthesis before the leaves emerge.

Eastern plane tree (Platanus) is a small genus of trees native to the Northern Hemisphere. They are all large trees to 30-50 m tall. They are often known in English as planes or plane trees. The flowers are reduced and are borne in balls (globose heads); 3-7 hairy sepals may be fused at the base, and the petals are 3-7 (or no) and are spatulate. Male and female flowers are separate, but borne on the same plant. The leaves are simple. The base of the leaf stalk (petiole) is enlarged and completely wraps around the young stem bud in its axil. The axillary bud is exposed only after the leaf falls off.