14 
Agricultural Experiment Station 
rupted by well defined diaphragms. With some exceptions the tissue at 
the nodes is composed of true pith cells but these are often so compressed 
as to give the whole structure the appearance of a partition as seen with 
the unaided eye. Sometimes, however, we do find true hard and woody 
Fig. 5. A leafy slioot from the 1913 Winchell-Rotundifolia hybrid, show¬ 
ing its type of shoot, leaf and tendril. Reduced. 
diaphragms. Often we find a complete separation or rent in the pith 
column just above the place where a diaphragm is supposed to be. The 
average diameter of the pith column of the hybrid is a little less than that 
of the two parent vines. 
