Cauliflory

Cauliflory——Mayodendron igneum

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People living in temperate or cold zones are familiar with flowers blossoming and fruits growing on branches and twigs of annual and vivacious plants; however, as soon as they step into the tropical rain forests, they will soon find that the scenes there are quite surprising to them. Bunches upon bunches or strings upon strings flowers and fruits are blossoming or growing on the thick forks or trunks of trees; and some even grow on the bottom part of the tree trunks. At such scenes, they are often surprised with their eyes wide open. As a matter of fact, this is a common phenomenon in the tropical rain forest; and the local people call the scenes "flowering and fructifying on old tree trunks". 

Male Flowers of Baccaurea  ramiflora Lour

If the visitors take a further observation, they will find that, no matter the plant of the yellow Mayodendron igneum flowers growing on the folks of the tree, or the red Baccaurea ramiflora fruits hanging on the old branches or trunks or strings of strings purple Ficus auriculata, they are not all tall arbor trees in the rain forests; instead, they are all arbor trees in the lower level of the rain forests. If the observers have sufficient knowledge in botany, they will also find that they are plants from different plant families. This explains that the phenomenon of "flowering on old trunks" has relations with the rain forest environment they are growing in. The plants in the rain forest, based on the spaces occupied by each other's canopies, are divided into three layers; i.e. the upper, the middle and the lower layers. The arbor trees of the upper layer are as tall as 30-40 meters in height, and their canopies are dense and deep; while arbor plants in the lower layer, often have a height of no more than 10 meters, and their canopies usually grow to next the lower part of the middle layer tree canopies. The problem with these plants is that, no matter they are in polygamy or in dioecism, they can only grow seeds after pollination by insects. If their flowers blossom on annual branches or twigs, it would be very difficult for them to display poises attractive to insects, for it is quite inconvenient for insects to fly in the dense living environment the trees are growing. Their flowers often bloom on old trunks or branches, because, those parts of the trees have a larger distance from the herbal plants and vines growing under them; therefore, the places are more spacious to attract the views and visits of insects. This is really the masterpiece of nature. "Flowering on old tree trunks" is a kind of adaptation of some trees to the rain forest environment. It is not a patent of a certain plant family; such properties of plants can also be passed down to the next generation. In Xishuangbanna Tropical Botanical Garden, the gardeners planted many such plants. The flowers of such plants still blossom on old trunks after they left the rain forests; but in some varieties, such as Baccaurea ramiflora, they will produce less fruits on their large trunks or branches. The reasons might be that they have left the shady and humid environment of the rain forests; or they attract fewer visits of the insects.