Some species of tree have sticky seed pods. You can learn to identify the trees that produce your sticky seed pods by looking at the other features of the tree that produced them, such as the leaves and the bark. There are trees native to Britain with sticky pods, but you may encounter non-native varieties in parks and arboretums.
Look at the seed pod. Kentucky coffeetree seed pods are flat, green, heavy and straight edged. They are filled with a sticky green substance containing 1.2 cm (1/2 inch) seeds. The seed pod of the monkey pod tree is 15 to 20 cm (6 to 8 inches) in length, straight, and dark brown, containing reddish-brown seeds that are sticky on the outside. Sweetgum tree seed pods are distinctive; they are also called porcupine eggs and are round, green or orange-green and covered in sticky spines.
Look at the leaves of the tree that produced the seed pod. The Kentucky coffeetree has compound leaves that are several inches in length. They have two rows of teardrop-shaped leaflets. Monkey pod leaves are compound, with long oval leaflets running in two rows. They are green to brownish-green in colour and have no stalks. The leaflets curl up at night and on cloudy days. Sweetgum leaves have three to seven pointed lobes.
Look at the bark of the tree that produced the seed pod. Kentucky coffeetree bark ranges from grey to brownish-grey. It often has deep irregular fissures and plates that are curled around the edges. The bark of the monkey pod is dark grey and has low, horizontal ridges. Sweetgum bark ranges from brown to grey and has vertical ridges. These might be either slight or deep.
Look at the tree's flowers. Kentucky coffeetree flowers are small, star-shaped, and white and yellow. Monkey pod trees have puffy pink flowers that are darker toward the edges. Female sweetgum tree flowers are pale green clusters of round balls on the end of drooping stalks. Male sweetgum tree flowers are yellowish-green clusters of balls on stiff spikes.