118 R. H. Compton. 
The Runners. 
The creeping vegetative axes are fine thread-like structures, 
circular in transverse section, branching infrequently and irregularly. 
At certain points four or five branches arise together (Fig. 7 C), one 
or more becoming an aerial leaf. The mode of branching suggests 
that the runner is sympodial, but in the absence of true leaves (see 
below) this could not be settled. At other points short lateral axes 
are produced, these usually terminating in bladders. The thickness 
of the axis is fairly uniform, but the bladder-stalks are somewhat 
narrower. 
Fig. 6. A well-grown plant arising from a propagating tuber (£.ii.) ; 
consisting of a tall peduncle (ped.) bearing a bract (by.) and terminating in a 
capsule (caps.) surrounded by the two segments of the persistent calyx (c) 
From the tuber also arise two leaves (/), and a number of runners (r) which 
bear laterally bladders ( b) and young tubers (t.i.) x about 4. 
The vascular system of the axis is very simple: a single 
continuous vessel extends along the axis, enlarging and forking at 
the nodes, The vessel is largely annular, but here and there spiral 
