251 



Expertmenls with inverted Stems. 



In the last number of the " Berichte der Deutsche botanische 

 Gesellschaft/' Professor Kny gives an account of some experi- 

 ments he has recently made with inverted stems. Hedera Helix 

 and Ampelopsis qimiqiiefolia were chosen for this purpose. In 

 1884 several plants of both kinds were selected whose stems 

 were about ten feet in length. These were so planted that both 

 the stem and root end were completely under ground; the cor- 

 responding parts of the stem were bound, each to a separate sup- 

 port and allowed to grow in this manner for one year. At the 

 end of this time the stem was carefully cut in the middle, or 

 highest point, and from this time until 1889, both the inverted 

 and the normally upright parts grew as separate individuals. 

 The plants with inverted stems showed from the first a strong 

 tendency to produce more and stronger buds near the real tip 

 of the stem, that is, just above the ground, than at the other end. 

 For the first year after the separation, only a few dwarfed buds 

 were developed from the upper, while they developed and grew 

 thriftily near the ground. The lowest of these were carefully 



removed each year, but the tendency to a richer production 

 m that region than elsewhere along the stem remained some- 

 what active. The upper, that is, normally lower end of the 

 stem also died down for some little distance shortly after the cut 

 separating the two parts was made. But in the next following 

 year or two, the uppermost side branches grew thriftily, and in 

 the spring of 1888 the inverted plants presented in general the 

 appearance of normally growing vines. The diameter of the 

 stem at the ground was perceptibly greater than at the upper 

 end. At the end of five years, or four if reckoned from the time 

 of their independent existence, the inverted plants appeared to 

 have accommodated themselves to their changed conditions. It 

 was now thought time to examine whether this change was 

 merely an outward one, or if it had reached deeper and affected 

 the entire nature of the plant. A method previously followed 

 by Vochting was used to determine this. Sections o{ stems 

 about twenty centimeters in length were cut from the inverted 

 plants and hung in glass jars, some in the same position as when 

 growing, others were inverted. The jars were kept in a dark 



