Trichomanes javamount, BL 1041 
of xylem diminishes; for instance, at a distance of 016 mm. from the leaf- 
trace the branch stele possesses six lignified elements (PI. LXXX, Fig. 5). 
This number is further reduced to two, and then to one lignified element at 
a distance of 0*23 mm. from the leaf-trace (PI. LXXX, Fig. 6). The phloem 
also loses its differentiation until the strand is composed of a small mass of 
deeply-staining parenchyma (PI. LXXX, Fig. 7). At this stage there is 
a distinct bulge in the cortex in which the strand is situated, and in some 
cases a break begins to appear between this portion and the rest of the 
cortex. Text-fig. 3 A gives a diagram showing the axillary branch, x , situated 
in a portion of the cortex which is separating from the rest by a break, br , 
in the cortex cells. This break is apparently brought about by the dissolu¬ 
tion of the middle lamella of these cells as shown in Text-fig. 3 B. Thus 
this tissue is gradually separated from the cortex of the petiole, and it dis¬ 
organizes along with the remains of the branch stele. In other cases the 
break is not so distinct; the portion of the cortex containing the axillary 
strand projects beyond the rest. It gradually diminishes in size, and the 
tissue becomes disorganized. There is no doubt that this is the tapering 
mass of tissue visible on the adaxial surface of the petiole base. 
From the serial sections of the stem and petiole bases it has been 
possible to reconstruct a longitudinal diagram of the course taken by the 
