Physiology of the Genus Cuscuta. 79 
If one cuts off branches of C. glomerata , for example, about 
six centimetres behind the tip, that is, cuts off the growing 
region, which naturally would not be likely to contain a large 
surplus of food, and fastens these cuttings by little ribbons of 
gummed paper upon the stems and erect branches of a suitable 
Impatiens , they soon begin to make close turns, and to develop 
haustoria which penetrate the host in the same length of time 
that they would consume were they still attached to the 
parent plant. To accomplish this large amount of growth 
they must have received food from outside, namely from the 
host about which they have twined. This food can at first 
have been absorbed only by the papillate epidermal cells, for 
these alone were in contact with the host. As has been shown 
before, these epidermal cells not merely come into and remain 
in contact with the epidermal cells of the host, but they 
penetrate these and therefore can absorb from the subjacent 
cortical cells which are richer in nutrient substances. Until 
the haustoria have themselves entered the host, these 
epidermal cells absorb all the food which the parasite receives 
from without. They are therefore, in a physiological sense, 
pre-haustoria , though in a morphological sense they are quite 
distinct from haustoria. 
Although these cuttings have made close coils, have formed 
haustoria, have sent these into the host, as quickly as if they 
had remained attached to the parent plant, yet certain 
differences are plainly to be seen between them and others 
which have performed the same operations while remaining 
unsevered from the parent. In both the cuttings and in the 
still attached tips, growth in length nearly, if not entirely, 
ceases when the formation of close coils begins ; but in the 
attached tips a marked increase in thickness follows the close 
winding, while no such evident growth in diameter takes place 
in cuttings, though a slight increase in thickness is sometimes 
observable. Owing to this growth in thickness of the attached 
tips and the consequent increase in the rigidity of the coils, 
the haustoria, in entering the host, are unable to push the 
parasite away, but all the pressure which they exert by their 
