54 R. T. BAKER AND H. G. SMITH. 
the cut face was not opaque, was quite mucilaginous in 
appearance, and could be readily drawn out into threads. 
The ‘tuber’ as can be seen from the photograph was formed 
of concentric rings from the centre to the outside, some of 
these rings were darker in colour than others, and altogether 
the appearance resembled that shown by the annual rings 
in timber. There were twelve rings in the specimen taken, 
so that if the rings are annual the tuber would be 12 years 
old. Radiating from the centre to the exterior were 
medullary rays, built up with vascular bundles, spiral 
vessels being very pronounced. A transverse section was 
composed almost entirely of ordinary cells, together with 
the spiral vessels of the vascular bundles forming the 
radiating portions. A very marked feature of a microscopical 
section was the presence of an abundance of raphides of 
calcium oxalate, and the ‘tubers’ of this species form excel- 
lent material for the demonstration of raphides in plant sub- 
stance. Portions were taken from several tubers and they 
all presented the same appearance. The raphides were in 
bundles of needles in the cells, and also as isolated needle 
crystals, radiating in all directions, or parallel. When a 
portion of the “‘tuber’’ was stained with an aqueous solution 
of rosaniline and afterwards cleared with glycerol, the 
ligneous portion of the ‘tuber’ was seen to be restricted 
almost entirely to the spiral vessels. A portion stained 
with iodine coloured alone the starch, and had no action 
whatever on the cell tissue. The starch granules had 
much the appearance of those of potato starch, but were 
generally smaller. There appeared to be no regular 
deposition of the starch in particular cells, and the granules 
were sparsely distributed through the mass. The amount 
of starch present could hardly equal one tenth of one per 
cent., judging from the microscopic determination and the 
result of the extraction. Inulin could not be detected; it 
was specially sought for in the aqueous extract at 50 —60° C. 
