-yy 



illustrated in the ash, figure 9. In the likic, as before men- 

 tioned, there are pra'ctically two terminal buds, and this leads 



w ^^ 



to another form of juncture shown in figure lo. 



Some extremely slow-growing horse-chestnuts and ailan- 

 thus trees, found in a rocky situation near New Bruijswick, 

 N. J., present striking illustrations of the point in hand, be- 

 cause what is usually found in a twig of several feet in length 

 is condensed into as many inches. The ailanthus, figure II, 

 illustrates the method of killing back of the tip each year, 

 and the renewal from a lateral bud. In fact, everything has 

 gone so irregularly that the storage of starch at the junctures 

 is far from uniform. In the ^sculus, figure 12 a, the case is 

 very different, and the progress, although small, is quite uni- 

 form. Looking at this twig from the outside, there is one 

 almost continuous display of bud-scale scars, so that the age 

 of the branch could be determined only with much difficulty. 

 On the other hand, by splitting it through the middle, the 

 empty, thin-walled, colorless sections of pith are quickly seen 

 as alternating: with those of a brownish tince. But the ereat- 



tj^' -^"- -■--' t> 



est difference is manifest when half of such a twig is laid for 

 a few moments in a dish containinii iodine, and afterward 

 washed in alcohol. It is then that the blue sections of pith 

 are seen to correspond to the basal part of each successive 

 terminal bud, and the empty pith separates them. The 



t> 



^senilis 



t> 



I 



I 

 I 



as in most twigs, and for this reason, when they lose their 

 normal amount of moisture by exposure, will shrink, leaving 

 depressions in the pith channel at these points, while the 

 empty, colorless pith between them retains its plump form 

 indefinitely. An examination of a similar yEscnhts stem, 

 made July 30th, showed that only a small fraction of the 

 starch still remained, and with almost none in the bud itself. 

 At b, in the same figure, the parts of a rapidly grown, long 

 horse-chestnut twig are shown in contrast with the slowly 

 developed branch at a. . 



SPINES AS RESERVOIRS OF FOOD. 



A study of the winter contents of the thorns of honey 

 locust, hawthorns, wild crab-apple and the Japan quince, etc.. 



