Gutta-percha tree
This is a genus of just one species from China but the catch is that it is dioecious and you therefore need separate male and female plants to produce green winged fruits on the female plants. When grown from seed you will, unfortunately, have no idea which sex the seedlings actually are until they grow on to maturity.
E. ulmoides is a hardy ornamental tree perhaps grown as a curiosity to catch out the knowledgeable tree expert with its rarity. It grows to around 40ft in height and is a broadly domed tree. The leaves are a glossy dark green, 3-8in long, with prominent veining. If the leaves are torn the pieces will be held together by rubbery fibres.
The flowers, such as they are, appear singly or in clusters before or with the leaves in spring. They are petalless and green.
It is the only hardy tree known to produce rubber.
