ON THE STRUCTURE OF THE BEET-ROOT: 277 
me externally ; it is separated from the central formation by a 
coloured or “obscure” medullary zone, which was the inner circle 
of the cortical parenchyma ; — the central formation there are 
two zones od cortical parenchym 
n examining a young plant fs ch had four leaves more than 
the preceding, we found the hypocotyledonary axis destitute of the 
external zone of cortical parenchyma, and only preserving shreds of 
i hat 
persistent cortical zone a new transparent circle made its appear- 
= gusts with — visible vascular —_* and separated 
om the second formation by a coloured zone var.) which 
t aood originally the inner circle of cortical fete hyma. 
In young plants which have the leaves still more numerous, 
there are medulla rolongations which divide the transparent 
zone of each formation into bundles corresponding with the woody 
bundles ; new formations appear in the external parenchyma, and the 
older ones take a more considerable developm ent. 
Lastly, in a Beet arrived at the termination of its year’s growth, 
even circular formations besides the central. e 
ar} 
= 
united in their lower portion, are elongated from within outwards, 
divided by medullary rays which penetrate irregularly into their 
thickness, and which are sometimes coloured, and preserve some 
bundles separate from the rest. These bundles are surrounded 
zone entirely white (white var.), or red in its external half Cred 
var. }. Round the central formation are circles of bundles formed 
8 
apparent in the older oon. contracted in their middle part 
because the bundles are enlarged, appoer ne: sometimes interrupted’ 
because this middle part remains transparen 
Each bundle is composed of an inner or woody portion formed 
of a vascular group ya ete Sterne by transparent tissue, orange 
‘(ved var.) or white (white var.), and of an external or cortical 
portion, which is ma iad oat from the medullary sotisamene or 
rays by the transparency of its boundaries. It may also be dis- 
tinguished by its colour; sometimes it is orange, when the medullary 
one is = an intense re 
art of this tissue nearest the vascular group is often more 
bund! 
rtical and ligneous parts of the bundles are more enlarged 
in the pce ae of the diameter of the root and more divided in 
