One such tree is the Cercis chinensis. It is a common flower - shrub in the Qilu region of China2. Its flowers not only cover the branches but also bloom on the trunk2. This phenomenon is known as "old - stem flowering"2. The flower buds of the Cercis chinensis are dark purple - red and turn rose - red after blooming. The flower clusters are like purple bead curtains, showing an excellent ornamental effect4. Another example is the Mayodendron igneum, a small - tree plant of the Bignoniaceae family. It is distributed in Taiwan, Guangdong, Guangxi, and southern Yunnan in China. Its trumpet - shaped flowers grow densely on the branches and trunks, presenting an orange - red color. The Cresentia alata, native to tropical South America, is also a typical "old - stem flowering" plant1. Its flowers are solitary and clustered on the old stems, with a corolla in the shape of a spathe and purple - brown markings1.

These trees have evolved such unique flowering patterns to adapt to their living environments. For example, in the dense tropical rainforests, the Cresentia alata is a middle - and - lower - layer tree species. Blooming and fruiting on the old stems can facilitate pollination by insects and avoid being attacked by strong winds and heavy rains, which is beneficial for reproducing offspring1. In addition, their thick trunks can bear the weight of fruits and a large number of seeds1.