C. A. BARBER 103 



or species and the amount of energy which each individual plant possesses. 

 The 6s develop more quickly than the «s, the cs more quickly than the &s and 

 so on, until towards the end of the season when the energy available has been 

 largely used up. This increasing rapidity in development is not to be wondered 

 at, when we consider the larger mass of leaves and roots and the greater thick- 

 ness of stems with their store of nutriment, as time passes and the plant becomes 

 larger. This difference in the rate of growth in branches of successive orders 

 leaves its impress on the final form assumed by the individual joints, especially 

 the lower ones, and this makes it easy to deduce the previous rate of develop- 

 ment from an examination of the dissections. At the point of origin, each 

 shoot is extremely thin, and its first effort is to increase its thickness, until that 

 appropriate to the variety has been reached. We have, empirically, but as 

 the result of many observations, assumed that, until the joints reach about 

 one inch in length, the shoot is still in this preparatory thickening stage, and 

 also engaged in the process of branching, for most of the branches are found in 

 this basal, short-jointed portion. And we thus obtain a useful indication of 

 the rate of development of any shoot, by measuring the length of the portion 

 before joints one inch long are reached. The as, or main shoots are all distin- 

 guished by a long basal portion. But we soon meet with another factor, which 

 influences the length of this part of the stem. This is, that the later formed 

 shoots have to place themselves between or outside the earlier ones before 

 they can start growing freely, and they accordingly take a longer time in passing 

 through their preparatory stage, the basal portion gradually becoming longer 

 again in branches of higher orders. 



In considering the way in which later shoots avoid congestion with the 

 earlier ones, we have to study the whole question of the orientation of the 

 buds on successive shoots, and the way in which the latter place themselves 

 in a favourable position for free growth. The main shoot of the sugarcane 

 plant, with its two rows of alternate leaves on opposite sides of the stem, 

 assumes the form of a fan, as is seen in PI. XVII, fig. 1. Each of these leaves 

 bears a bud in its axil, and the branches, if developed strictly, should all 

 be formed in the same plane. Each of these branches has a series of leaves, 

 of which the first or lowest bud scale lies in the same plane, and, there- 

 fore, unless some disturbing influence supervenes the whole plant with all 

 its complex of branches and leaves, if laid out on a table, would be flattened 

 out in one plane. But this strictness of arrangement is usually avoided 

 in nature, for the branches would interfere with one another and the 

 distribution of light would be uneven. Thus, in Pandanus, where the 

 le9,ves are arranged in a series of rows, there is an obvious but gradual torsion 



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