46 



THE GAEDENEE'S ASSISTANT. 



Generally speaking, the plant as it grows 

 commences to subdivide by the formation and 

 development of "growing-points", aggregations 

 of cells which divide very rapidly and eventually 

 break up the original unbranched body into 

 numerous subdivisions or branches. Such grow- 

 ing-points, of course, occur at the tips of the 

 roots and the ends of stem and branches, and 

 are sometimes developed from the sides. In 

 all cases their structure is similar, and at an 

 early stage of their existence it is easy to recog- 

 nize, by the position and direction of the con- 

 stituent cells, three portions : an outer, protective, 

 which becomes the epiderm; an intermediate, 

 mainly constructive, which becomes the cortex; 

 and an inner, mostly or chiefly conductive, which 

 becomes the central cylinder of fibro-vascular 

 tissue. 



If the force of growth be about equal in the 

 subdivisions, and the latter are about equal 

 in size, then we have forked branching, as in 

 the veins of ferns; or we may have pinnate or 

 palmate modes of branching, as already men- 

 tioned in the case of leaves. 



The variations in form according to the 

 greater comparative energy of growth at par- 

 ticular places have already been mentioned, but 

 it is further necessary to allude to two principal 

 modifications which are of great importance 

 to gardeners, viz. the indefinite or "centripetal", 

 which is contrasted with the definite or "centri- 

 fugal " mode of growth. In the indefinite mode 

 growth goes on either from below upwards, or 

 from without inwards, so that the topmost or the 

 innermost portions are the youngest. In the 

 definite modification, the topmost or the outer- 

 most parts are the oldest. It will be seen what 

 an important thing this is in relation to priming 

 and training, and it will necessarily be alluded 

 to again in considering the inflorescence. 



Buds. 



Growth may be, but very rarely is, con- 

 tinuous. Most commonly, especially in the higher 

 plants, with which we have particularly to deal, 

 growth is arrested after a time, owing to a di- 

 minution in the temperature or moisture, and 

 is resumed when conditions once more become 

 favourable. Thus it is that "winter buds" are 

 formed. These are growing-points at the ends 

 of the shoots (terminal), or at the sides (lateral). 

 When lateral, or "axillary", they spring from 

 the side of the stem just above the place from 

 whence the leaf springs, from the " axil " of the 

 leaf as it is said. The growing -points are 



invested by numerous overlapping bud-scales, 

 which are merely imperfectly-developed leaves, 

 destined for the purpose of protecting the young 

 growing-point and its nascent leaves from the 

 effects of cold or excessive evaporation. The 

 leaf-like character of these scales will be obvious 

 to any one who will examine the unfolding 

 buds of the Horse-chestnut or Maple. These 

 buds may be purely leaf -buds, when they will 

 eventually lengthen into shoots, and these will 

 harden into branches; or they may be purely 

 flower-buds, when they contain rudimentary 

 flowers only ; or they may be mixed buds, partly 

 leaf-containing, partly flower-bearing. In either 

 case the arrangement is essentially the same. 



One point of great importance to gardeners 

 is the development of the flower-buds on "last 

 year's wood", or on "spurs" or short branches, 

 as in the apple or red currant, In this case the 

 flower-buds were formed in the autumn previous 

 to their expansion, and may be detected all 

 through the winter. In other cases, as in the 

 vine, the rose, or the black currant, the buds are 

 formed on the young herbaceous shoots formed 

 in the same season as that in which the flowers 

 expand. The method of pruning, of course, must 

 be modified accordingly. Though so important 

 culturally, this difference, great as it appears to 

 be, is less important to the systematic botanist, 

 seeing that different species of the same genus, 

 e.g. red and black currants, or of Clematis, 

 though so very closely allied, yet differ in this 

 particular. 



Sympodes. — Sometimes, when two growing- 

 points are formed, instead of the resultant 

 branches growing equally one grows faster and 

 stronger than the other, or one shoot will in 

 course of growth supplant its neighbour and 

 take its place. Thus, in the vine it will be 

 noticed that the tendrils and the fruit-bunches 

 are opposite to the leaf. Originally, as may 

 readily be seen in the young shoot, the tendril 

 or the flower-bunch is "terminal", that is, placed 

 at the end of the shoot, but, as growth goes on, 

 the tendril or the bunch turns to one side, 

 whilst growth in the direct line is carried on by 

 the new shoot formed in the axil of the nearest 

 leaf. Such a mode of branching, where one 

 shoot usurps the place of another, is called 

 " sijmpodial", the main shoot here being made 

 up as it were of several generations or " podia " 

 placed one over the other, in contradistinction 

 to the " monopodial " growth, where the main 

 shoot is unbroken and continuous. 



Detached Buds; Cuttings. — Sometimes the buds 

 detach themselves naturally from the plant, or 



