Alder or "brown", which is also a root for the English words "elk" and another tree: "elm", a tree distantly related to the alders. With a few exceptions, alders are deciduous, and the leaves are alternate, simple, and serrated. The flowers are catkins with elongate male catkins on the same plant as shorter female catkins, often before leaves appear; they are mainly wind-pollinated, but also visited by bees to a small extent. These trees differ from the birches ("Betula", another genus in the family) in that the female catkins are woody and do not disintegrate at maturity, opening to release the
Eucalyptus deglupta flower buds contain stamens and pistil and are usually pollinated via bee. After fertilization, the flower capsule becomes a woody fruit, known as a gum nut, which contains the seeds. The unique multi-hued bark is the most distinctive feature of the tree. Patches of outer bark are shed annually at different times, showing a bright green inner bark. This then darkens and matures to give blue, purple, orange and then maroon tones. The previous season’s bark peels off in strips to reveal a brightly colored new bark below. The peeling process results in vertical streaks of red, orange, green, blue,