In most species only a single bud develops in the axil of each leaf. In some, however, two , or even more may may develop, The bud nearest the terminal of the shoot is usually the largest of the group and is named the primary hub. Commonly, however, all except the primary bud are referred to collectively as the secondary, or reserve, buds. The p[remarry bud is the one of the group most likely to grow when the tree starts growth in the spring. The reserve buds oftentimes begin normal growth with the primary buds, but they are especially likely to grow under conditions of excessive soil moisture or if the growth from the primary bud is injured by cold weather, insects, or other causes.
Vegetative and Flower Buds.
The growth in height of a plant and the production of branches is due to the growth of vegetative buds. These are also called leaf buds.
Flower buds contain the rudimentary blossoms with various parts of the flower enclosed. Since flowers normally produce fruit as they continue to grow and develop, these buds are also known as fruit buds,. Flower buds develop from, of in close association with vegetative buds ;  hence, they occur on plants in the same general position as vegetative buds. In others, the two are quite similar in appearance.  The formation of flower buds takes place in some species during the season pro virus to the own in which the flowers appear. In other species the flower buds do not form until a time shortly before the buds begin to grow. In the peach, for example, the flower buds that boom in the spring ate formed during the previous summer and fall. Flower buds of citrus develop in late winter or early spring preceding the blooming period. An accumulation  of stored food in a plant is regarded as favorable for fruit-bud formation, and this accounts for the considerable variation in the time within a species when flower buds are formed.
Some species of plants produce mixed buds. The contain both flowers and vegetative parts within the same bud; consequently, when they begin growth they prejudice both vegetative in the time within a species when they produce both vegetative growth and flowers. The apple, pear, and blackberry are plants that produce mixed buds.
Dormant and Latent Buds :
 The buds of most fruits develop and mature during a given season and remain dormant over winter. Such buds begin growth the following spring and either develop into shoots of fruits or fall off, or they may remain dormant for a period of one to several years, in which case they are called latent buds. They may even become covered over by layer of bark; however,these latent buds usually make sufficient annual growth outward to prevent them form being over walled. When trees are cut back heavily, any of the 'water sprouts' that develop arise from latent buds
Adventitious Buds :
Normally shoots arise from well- formed buds, but occasionally they develop from other tissues, which form adventitious buds and shoots that grow from these are called adventives. Those that arise from foots are known as ‘suckers’ form example buds of the pear, blackberry, and persimmon plants. The point  of their origin is in the cambium of roots. Adventives shoots may also arise from stems. These originate principally in the cambium layer. Those that occur on the body or framework of trees and which make rank, venous growth are called ‘water sprouts.’ Most such shoots, however, arise from latent buds. Adventive shoots, however, arise from latent buds. Adventive shoots are also produced readily by leaves of some plants and less readily by others. The shoots originate from parenchyma  tissue close to the vascular bundles in leaves of dicotyledonous plants; and frequently from callus, formed at the cut or injured portion of the leaves of monocotyledonous plants.
Leaves :
Mineral nutrients and water from the soil are combined with carbon dioxide in the leavers, under the influence so sunlight, to form plant foods essential to growth. Leaves are later appendages formed by the stem in elongation. Plants that shed their laves at certain seasons, and hence have a period during each yearly cycle when they are bare and another when they are in full foliage, are known as deciduous plant. Examples are peach and apple. Those that retain their leaves for long periods, and do not shed all of them at one time but shed them so gradually that the trees have leaves on them at every season of  the year, are known as evergreen plants. Broad-leaved every greens are represented by such plants as citrus and cherry laurel, which retain their leaves form more that on year, and by other such as the live oak and ya upon, which retain them only until new le3aves are formed the following spring. The pines, arborvitaes, spruces, and junipers are examples of the coniferous evergreens.

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