Spratt.—Some Anomalies in Monocotyledonous Roots, ioi 
dermatogen, and the third to the calyptrogen, which . is the normal arrange- 
ment in Monocotyledons roots. Where is the meristem which produces the 
secondary elements ? This point was definitely elucidated by Cordyline 
Shepherdii , which is a near relative of Dracaena, a member of the same 
subdivision of the Liliaceae and greatly resembling Dracaena in appearance. 
The structure of the root is precisely the same as in Dracaena , except that 
in this species, even in the largest roots, the xylem and phloem groups are 
apparently never budded off into the pith. Apart from this detail there is 
one difference which became at once apparent, namely, the pericycle is 
many layered. On examination it is evident that the pericycle in fact acts 
as a meristematic layer, and here no doubt the new vascular elements 
originate (see PI. Ill, Fig. 2 ). Dracaena being re-examined, it was discovered 
Transverse section of rhizome of Cordyline Shepherdii with an emerging root. 
Diagrammatized. 
that the pericycle cells, as in Cordyline, have contents and they could be 
seen producing new elements. With this may be correlated the fact that 
in the Dracaenas and in Cordyline , in any transverse section, some of the 
vessel-like tracheides have unthickened walls which undoubtedly thicken as 
the root matures. 
Cordyline , as mentioned, is in every way similar to Dracaena. With 
regard to the root, however, there is a distinguishing feature in the fact that 
Cordyline possesses a rhizome (see PL III, Fig. 8). This rhizome shows the 
typical structure of a secondary thickened stem, namely, the central primary 
vascular bundles and the outer secondary ones. The roots arise endo- 
genously from the rhizome, and when this takes place several of the stem 
vascular bundles appear to coalesce and form a structure like the primary 
root stele. At first this stele possesses no endodermis, but this arises when 
the stele enters the root (see text-figure). 
