6 



STRUCTURE AND PHYSIOLOGY OF THE PLANT 



or round potato is an example, and also the creeping rhizomes of quack-grass and other grasses. It 

 will be noted, from this discussion, that the botanist, by the word stem, means to designate the leaf- 

 bearing axis and its branches and modifications, and not the 

 stalks of leaves and flowers. Thus, in the plantain and dandelion 

 (Figs. 5, 26), the stem is very short, bearing a rosette of leaves 

 at the ground ; and from this arise the flower-stalks. In useful 

 products, the stem provides timber, some of the fibers, and 

 much of the forage ; and it also provides human food, as in 

 the potato, asparagus, onion, kohlrabi, sugar-cane. 



The leaves arise normally from the joints or nodes of the 

 stem. Usually a bud is borne in the axil or upper angle made 

 by the leaf with the stem. The bud is a very short and unde- 

 veloped branch. If the plant is dormant a part of the year in 

 consequence of cold or dry, or because of other hereditary habit, 

 the leaf usually falls and the bud remains quiescent till the 

 growing season returns : it is then spoken of as a winter bud. 

 Sometimes the bud remains quiescent, but alive, 

 for a longer period, in rare cases even for 

 years : it is then called a dormant bud (Fig. 

 6). The older the dormant bud, the less the 

 likelihood that it will grow, in case necessity 

 should arise. The common notion that old dor- 

 mant buds are readily forced into growth by 

 pruning needs correction. In cases of heavy 

 pruning, new shoots on old wood are more 

 likely to arise from buds that are formed for the 

 occasion, without reference to leaves and with- 

 out order ; these are known as adventitious 

 buds (Fig. 7). 



If the bud " grows," — that is, if anything issues from it — it produces a branch. The branch may be 

 exceedingly short, and bear only one or two leaves, or it may be several feet long and bear many leaves. 

 If its destiny is to produce only foliage, it is known as a leaf-bud ; if to produce flowers, it is known 

 as a fruit-bud or flower-bud. Peaches and apricots produce typical fruit-buds (Figs. 8, 9). Apples and 

 pears bear both true leaf-buds, and fruit-buds that give rise to flowers and leaves (Figs. 6, 10) — for 

 the flowers of these trees are in clusters or bouquets accompanied by foliage. 



Fruit-buds are distinguished by shape and position. In shape, 

 as compared with leaf-buds they are usually relatively broader 

 and more rounded, and they are likely to be more conspicuously 

 fuzzy (Figs. 6, 8, 11). The posi- 

 tion of the fruit-bud varies with 

 the species. In most of the pome 

 fruits — apples and pears — these 

 buds are on spurs (very short 

 branches. Fig. 6), or sometimes 

 terminal on long axial shoots. In 

 peaches, the fruit-buds are lateral 

 on the current year's growth, usu- 

 ally one on either side a leaf-bud 

 (Fig. 8). In plums and apricots, 

 they are both on spurs and lateral 

 on the long growth. The produc- 

 tion of fruit-buds may be influ- 

 enced to some extent by pruning, 

 although this influence is not ex- 

 act and definite. Pruning should 

 always be practiced in full knowl- 



Fig. 5. A so-called stemless plant {narrow -leaved plantain), the 

 stem rising little above the ground. The long flower-stalks (in 

 such cases called scapes) spring from the stem. 



Fig. 6. Fruit-buds of apple, on 

 spurs; a dormant bud at the top. 



Fig. 7. Adventitious shoots or "suckeis." 



