1895. ] Vegetal Dissemination in Opuntia. 357 
three inches long, two inches wide and from one-half to two- 
thirds of an inch in thickness. On the tenth of the same 
month I observed a branch developing at one of the upper 
tubercles. 
The specimen began to attract my attention and on weigh- 
ing it I found it weighed 11.78". The ten days intervening 
from the time the specimen was procured until it was weighed 
it undoubtedly lost considerable by evaporation. In the 
meantime, however, the large wound, caused by cutting the 
joint lengthwise had become practically impervious to evapo- 
ration by the exuding of the mucilaginous substance of the 
adjacent cells forming a thick scab-like crust over the 
wound. 
The branch continued to grow rapidly while the old stem 
began to wither at the point farthest away from the branch. 
This process continued much in the same manner, month after 
month, during the entire summer. Not a single drop of 
moisture came in contact with it after it was placed in the 
b 
Ox. 
On the twentieth of January of the following year the 
specimen weighed 10.016™, losing in six months a little over 
fifteen per cent. of its total weight. At this time the branch 
had grown to be five and one-fourth inches long, or nearly 
twice the length of the old joint. It was, however, very 
slender and thin. 
About seven-eighths of the old stem was dry and hard, but 
the portion immediately surrounding the base of the growing. 
stem was as fresh and green as ever. 
The next observation was on April fourth. At this time 
the specimen weighed 9.259™. The old stem was now en- 
tirely dry; the branch was nearly six inches long and as fresh 
asever. By the middle of May the branch began to wither, 
but a new one had begun to develop about an inch from the 
per cent. of its weight at the time of the first weighing. No 
further observations were made for a period of f 
On my return from the east in September the entire plant 
Was dry. : 
The persistency with which cylindropuntias retain their 
