286 
BRYCE : 
and (2) nodules independent of buds, which are again divided 
according as the central core consists of wood elements, of 
bast elements, and of cork tissue. Wood elements form the 
core in the majority of nodules, cork tissue is found in some, 
and bast elements were observed in only a single case. The 
nodules which occur in connection with dormant buds or 
abortive shoots, which have subsequently become separated 
from the stem wood, must be clearly distinguished from those 
nodules which originate as isolated bodies in the cortex. 
Krick thus considers beech nodules to arise from dormant 
buds and abortive shoots, or to be new formations. 
Frank (10) comes to a similar conclusion from his own 
observations, and from a discussion of the papers of Krick, 
Sorauer, and earlier authors. 
Under Küster ’s (19) arrangement of plant pathology Hevea 
nodules would come under Hyperplasie, sub-section Hetero- 
plastic Tissue, and would be classed near wound wood as 
“ tissue resembling wound wood,” included in which section 
are nodules of beech, pear, and apple. This classification is 
not quite satisfactory, as the structures described as “tissue 
resembling wound wood ” appear sufficiently distinct to 
merit a more detailed definition. 
The presence of globular shoots in Hevea brasiliensis cau be 
fully accounted for within the normal life of the plant. 
“ Every plant-body forms more primordia of organs than it is 
able to bring to maturity. Just as by far the greater number 
of seeds which are annually formed are destroyed, sometimes 
because they do not find favourable environment for their 
development, sometimes because they are overcome by other 
organisms in their ‘ struggle for existence,’ so also some of 
the primordia of organs remain undeveloped because the 
plastic material which they require for their unfolding is taken 
by others which exercise a stronger attraction upon it ” 
(Goebel, p. 207) . Thus, of the buds laid down in a leaf axil one 
develops into a shoot, while its correlation with the other buds 
in the leaf axil results in their suffering arrest in development. 
That these arrested buds remain capable of development 
is seen in the abundant production of new shoots from 
old stems under suitable change of conditions ; consequently 
