View palm trees

Author: Liu Haisang (Compiler)
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Publishing Date: 2005-01-01
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(3) Formation of Inflorescences Most palm plants produce several inflorescences each year, but a few produce only one per year, and an extremely small number produce only once in their lifetime—once they flower. Inflorescences can be divided into two major basic types based on their position of attachment: terminal and lateral. The former refers to inflorescences that grow at the top of the stem; the latter refers to those that grow on the side of the stem. Lateral inflorescences can be further categorized into three scenarios: When there is no obvious stem or it is an underground stem, the inflorescence remains attached near the ground level, known as a basal inflorescence. However, more commonly, they are interfoliar (growing in the axils between leaves and stems) or subfoliar (growing on the stem below the leaf sheath) (see Figure 3—16). Terminal inflorescences are often large, and after fruit ripening, single-stemmed palm plants like the betel palm (Areca catechu) die entirely. Clumping palm plants, such as the Middle Eastern dwarf palm (Nanorrhops), can continue to survive through the trait of suckering, but the initial plant that produced the inflorescence will completely stop vegetative growth. Therefore, both types of palm plants are called "once-flowering" plants—once they flower, they fully enter reproductive growth and no longer undergo vegetative growth. The plant or vegetative part begins its countdown to life. Some palm species have multiple inflorescences growing near the top of the stem in the axils of leaves, blooming almost simultaneously, known as near-terminal inflorescences. Since the vegetative part gradually dies after flowering, this type of once-flowering is only seen in the Calamus family. Most palm plants have lateral inflorescences, which develop and mature in two ways. One way is that when the plant reaches a certain stage of growth, lateral inflorescences appear one after another from top to bottom. These inflorescences develop and mature from top to bottom. When an inflorescence reaches near the ground level, for single-stemmed plants like the fishtail palm (Caryota), the entire plant dies. For clumping plants like the short-stalked fishtail palm, the vegetative part that produced the inflorescence dies, but the plant itself can continue to survive by producing new vegetative parts through suckering. This is also known as once-flowering. Such inflorescences are called geotropic (or terrestrially oriented). Most palm plants produce inflorescences from bottom to top, and vegetative growth does not stop due to reproductive growth, continuing indefinitely. This type allows for multiple flowering and fruiting. Such inflorescences are called aphanotropic (or non-terrestrially oriented). They include both interfoliar and subfoliar inflorescences. In reality, basal, interfoliar, and subfoliar inflorescences sometimes have no absolute boundaries. Essentially, they are all axillary inflorescences, differing only in their position of attachment and whether the leaves at the attachment point fall off. For example, the dwarf rattan palm can sometimes form stems as tall as 2 meters or even higher, at which point it is no longer a basal inflorescence but an interfoliar one. Sometimes, an inflorescence develops in the interfoliar position and, after maturing, the leaf falls off, transforming from an interfoliar inflorescence to a subfoliar one. The flowers of palm plants are usually not ornamental, but the inflorescences can have certain ornamental value. For example, the betel palm (Areca catechu) has extremely high ornamental value—its inflorescences are tall and spectacular, reaching about 7 meters in height and producing millions of small flowers. Another example is the purple-spike coconut palm (Cocos nucifera), where the inflorescence peduncle bracts and flowers are also purplish-red, giving the entire inflorescence high ornamental value. The bracts of the hooked-leaf vine are neatly arranged in two rows, displaying a particularly elegant posture. When designing landscapes, it is essential to consider whether the plant is once-flowering. Once-flowering plants exhibit a strong life rhythm, reflecting changes in time and serve as excellent materials for science popularization and sightseeing. However, they can also pose some problems. For example, certain single-stemmed species, like the fishtail palm (Caryota), need to be replaced after (about a decade or two). While the short-stalked fishtail palm (Caryota mitis) can produce new vegetative parts through suckering to continue surviving, it is not suitable for planting on steep slopes, as its dead leaves are difficult to remove, especially when the vegetative part that dies after flowering is not easily cleared.