250 
R. H. Compton. 
structure of the Viciem, with “ medullary ” xylem and extra-stelar 
stipular bundles: higher up this gives place to the development of 
a fistular pith and a single ring of collateral vascular bundles. In 
the uppermost region of the swollen funnel-shaped axis, however, 
two continuous concentric rings of vascular tissue are present. 
The outer of these rings is directly continuous with the single ring 
of bundles below, and the different vascular elements of xylem, 
phloem, etc., have the normal orientation. The inner ring, on the 
Fig. 1. Diagram of the fas- 
ciated portion of the stem, as seen 
if split longitudinally : above, a 
scheme of half the annular apical 
meristem. (In the bundles xylem 
is black, phloem left clear. c.c.— 
central cavity of the funnel; p.c. = 
lysigenous cavity equivalent to 
the fistular pith). 
Fig. 2. T.S. of a bundle of 
the internal system. (ep.= in¬ 
ternal epidermis, with stoma ; 
cort = cortex ; end= endodermis ; 
/>./. = pericycle fibres ; ph.= 
phloem ; «wfi.=cambium ; xy.= 
xylem!. 
