414 NATURAL SCIENCE. dec. 



The Growth of Plants. 



Nature does not pose as a graceful designer in the rectan- 

 gular inflorescence of Siphonychia diffusa, according to the descrip- 

 tion which Aug. F. Foerste gives of it in the Bulletin of the 

 Torvey Club. "Here is a plant," he says, "with its flowers laid out in 

 rectangular inflorescences — cymes with a flat top with quadrate 

 outlines, or of a form which at once makes us wish to say 

 parallelopipedon, as though the other dimensions were equally stiff 

 and rectangular. In these rectangles, the flowers are laid off almost 

 with the precision of corn rows in a field." This general effect is not 

 lessened by the way in which the inflorescences are arranged on the 

 stem. The latter is almost prostrate, and the cymes terminate the 

 branches at such heights as to fall approximately all in the same 

 plane, and being moreover disposed with their diagonals vertical or 

 parallel to the stem, their sides all become parallel, "so that the final 

 effect is that of a series of rectangular fields, set out in some western 

 landscape, where all lines run north and south or east and west." 

 The writer adds, "the plant must be seen to be appreciated." 



The same author also calls attention to the renewed growth of 

 trees in summer after having already once formed their terminal 

 scaly winter buds. In the formation of the buds the plant is 

 planning for the future; in many trees, the warmth of spring has 

 hardly called the vital functions back into vigorous action before the 

 growth for the year is completed, and a few weeks later a well-developed 

 terminal scaly bud awaits the winter. Considerable maturing may be 

 needed before all the characters necessary to withstand the winter's 

 cold are acquired; but the fact is evident that "the more terminal 

 leaves have remained in the crude state of scales when all the fresh- 

 ness of spring was inviting them on to full development to vigorous 

 leaves." 



The buds represent a year's growth, and before this year's is 

 finished the tree begins to prepare for the next year's task. Hence 

 there is a certain definiteness to the work, and we can foretell in a 

 measure how much the plant will do from year to year. This 

 definiteness must be related to conditions of climate found in certain 

 areas of the plant's distribution. Northwards the relations between 

 the number of leaves necessary for vigorous development, and the 

 provisions for the same, are so well balanced, that it is rather rare 

 to find woody plants renewing their growth after having once formed 

 their terminal buds. These correlations, however, lose in value in 

 going southward, and many trees, after having already formed such 

 buds in the spring, start growing again in the summer, and 

 again form terminal buds. Under exceptional conditions this may 

 take place three or four times in the course of a year. In the 

 black-jack oak [Quercus nigra), near Bainbridge, in Georgia, the 

 author found cases of repeated renewal of growth very common. In 

 the older trees such a growth has taken place twice this year on 



