172 OBSERVATIONS ON DRACÆNA RBFLEXA. 
One more point remains to be dealt with. According to 
Strasburger the roots of D. refiexa are epinastic, the 
secondary thickening beginning on the upper side and 
continuing to be more vigorous there. Certainly the peri- 
cyclic cambium is highly eccentric, and several areas of 
activity can only be explained in terms of the idiosyncrasies 
of the particular pericyclic cells. In the primary root, 
which has a fairly regular and downward course, the peri- 
cycle develops a cambium on one side only ; similarly, in 
secondary roots and in lateral branches exhibiting positive 
geotropism. The only relation that could possibly be 
established was that the cambium was active on the side from 
which a rootlet emerged, but as this occurred on any part of 
the mother root no “epinastic ” development could be said to 
exist. A similar arrangement has been described by Scott 
and Brebner for D, Draco and D. fragrans, and the eccentric 
development correlated with the proximity of the lateral 
root. 
The stele of the roots, though of the usual polyarch exarch 
type, seems to be liable to variation. A cortical injury 
often caused a breaking of the endodermis on one side, and 
this layer then curved inwards at each end and produced an 
arc similar in outline to that which monostelic systems often 
assume in their transition to other forms. In cases of con- 
genital concrescence a transverse section reveals two separate 
monosteles, which when traced upwards into the older 
portion fuse in a regular manner producing a single polyarcb 
stele. 
Explanation of Plate HI. 
“ Dracæna reflexa, Lam.” 
(Illustration reproduced from a photograph by L. Maddock, Esq., the Studio, Kandy.) 
The tree is fifty-four years old ; circumference of stem = nearly H 
metres ; height of tree =10 metres ; total spread of foliage = 0 
metres. Scale, nat. size. 
