Amphicarpaa monoica. 285 



twine, however, and the growth of the cotyledonary shoots 

 in all respects is about equal. 



Axillary Shoots. 



Let us now turn attention to the cotyledons of a plant 

 which has developed without accident. Examining the 

 conditions below the soil, it is found that from two to five 

 runners arise in the axils of the cotyledons. These usually 

 remain underground, and are therefore white, bearing 

 stipules, but no leaves. For a time their growth is com- 

 paratively slow. Plants in the woods, developing from 

 seeds in the spring, showed about July 1st, cotyledonary 

 axillary shoots from three to six inches long. Those raised 

 in pots were not so long, but were more branched. As the 

 summer advances, these runners elongate rapidly, and 

 eventually may become twenty to fifty or even sixty inches 

 in length. 



In the axils of the green leaves both simple and com- 

 pound, arise branches, which may be referred to as axillary 

 shoots (Plate XXII.). In the case of the simple leaves, two 

 to four, occasionally six, of these are found. Possibly here 

 the term "runner" maybe more appropriate. The com- 

 pound leaves show one, often two axillary shoots. All of 

 the axils of leaves upon these original branches possess 

 similar possibilities. One may easily imagine therefore the 

 mass of vegetation resulting from a healthy plant, from 

 which axillary shoots three or four feet in length are 

 actively growing. 



This development in the axils does not begin until the 

 plant reaches the height of ten to fourteen inches. Some- 

 times their increase is so rapid, that growth of the main 

 stem is evidently retarded. 



Apogeotropic and geotropic tendencies. 



Plants resulting from terrestrial seeds twine more or less 

 vigorously — and the main stem is decidedly apogeotropic. 

 The axillary "runners" are geotropic ; as soon as the bud 



