A Detailed Explanation of the External Structure and Morphological Characteristics of Cacti
The vastly different external features of different plants are almost always closely related to their specific ways of growing. Although sometimes people can only guess at what significance a plant's morphology has for its growth, these guesses are often the beginning of new discoveries. Moreover, if we merely described and explained technical terms in a purely academic way, it would be far too dry and dull for most readers. Therefore, this feature is dedicated to explaining the external structure of cacti in connection with the significance it may have for the plant's growth.
Caption: Cactus structure
The most striking thing about cacti is their morphology. From tree-like cacti over 20 m tall to single-stemmed columnar forms, as well as spherical or leaf-like forms, the variety is too numerous to list. The earliest cactus family plants were probably shrub-like, that is, with many branches and lateral buds slightly above ground level. In some species, the lateral buds grew upward above the ground and gradually evolved into tree-like species. In contrast, those species that retained their early morphology to a greater extent became columnar, or even spherical or leaf-like cacti with fewer or no branches. These evolutionary developments among the various species of the cactus family must have occurred independently of one another, because species reflecting the characteristics of each stage in this evolutionary history often appear within a single genus. For example, in the genera Echinopsis and Echinocactus native to South America, there are both columnar and spherical species, as well as various transitional forms between these two types. The North American genus Echinocereus also shows this situation.
A plant's morphology is of great significance to its growth. Tall tree-type cacti need ample rainfall and are also the most robust by nature. They have the most extensive root systems, and once they take root they often remain in place for a hundred years. Tree-type cacti in nature are often spaced far apart, and within their territory seedlings or cacti of other species or genera rarely appear. But this does not mean there are absolutely no scattered seeds among them. In fact, people have indeed found seeds scattered within them in certain geological tests. When there is sufficient rainwater, these seeds soon germinate. But not long afterward, when the land becomes dry, almost all the seedlings wither and die. This is because the soil layer below is almost entirely filled with the interlacing fibrous roots of those adult cacti. The taller the plant, the more extensive its root system and the more water it can store. Therefore, relatively speaking, where tall cacti grow, the least water can evaporate from the surface. In such a soil environment, seedlings rarely have a chance to survive their first dry season. Only when an old cactus dies or is transplanted do the small cacti near it have a chance to thrive, and only then can newly germinated seedlings possibly survive.
Generally speaking, smaller plants receive less light than large plants, because the branches and leaves of large plants block the sunlight. But for cacti in arid regions, getting enough light is hardly a problem. Because their root systems are extensive and well developed, cacti of the same morphology can hardly grow close enough to shade one another. On the contrary, species with very different morphologies, such as large shrub-like cacti and the small spherical cacti growing beneath them, differ greatly in their access to conditions such as water and sunlight . In particularly arid desert zones, only shrub-like and small spherical cacti can survive. Although they also branch, the lateral buds either fall off as soon as they emerge from the surface or before they even emerge (as in the so-called sprouting types). Some parts of these plants break off easily and roll a short distance away on the ground or stick to animals' fur and are carried away. These "seedlings" take root easily, so they can bypass the most delicate and sensitive stage of the seedling period. In addition, broken-off parts of shrub-like, many-jointed cacti also survive easily; even the cut stem of a completely unbranched columnar cactus (which, it should be said, is inherently unsuited to this method of asexual reproduction) can take root.
For friends who love cacti, this propagation method is very simple to carry out, and its advantage is that through this method one can obtain offspring with exactly the same genes as the mother plant.
Recommended articles:
Spiny cacti come to the dining table as flower growers happily sell busily
"Lazy person's plant" cacti also need care
Small potted plants are sought after in summer, with cacti among the top
Cacti shed their high-price "outer coat" and are replaced by low prices
Cacti are "tough," but pest control is still indispensable