64  Bunting—The Structure of the Cork Tissues in 
lines to the Agvimonice ; from this group or from ancestors 
intermediate between it and /otentillee there may have 
diverged on the one side the ancestors of Roseez, and on the 
other those of the Spirgee. A more direct line would lead 
to the Rudee, the three just named in their highest examples 
having all reached about the same degree of differentiation. 
Lines of specializing development would lead respectively 
from the Rubee to the Prunee, Amygdalee and Pomee. In 
my investigations upon the cork region of the above Rosaceous 
genera, the degree of specialized development reached in the 
cork cells of the different groups would seem to indicate in 
this respect such a relationship of the groups within the order. 
(2) Summary of Results ——1. Large intercellular spaces are 
present in the cork region of the herbaceous genera, smaller 
spaces in the shrubby genera of the order Rosacea. They are 
absent in the arborescent genera studied. 
2. A marked characteristic of the herbaceous and shrubby 
genera of Rosacee is the annular arrangement of the cells of 
the periderm region. In the arborescent specimens studied, 
the annular arrangement is not a feature of the periderm 
region. Results obtained from the study of this annular 
arrangement, suggest that each ring corresponds to a year’s 
growth. 
3. In herbaceous and shrubby species, a notable feature is 
the presence of a uniseriate layer of cells in which a lamella of 
suberin is present in the cell walls, this may or may not be 
present in the multiseriate layers. In very young roots the 
condition noted in Vines’ text book is sometimes found, namely 
that the radial walls alone of the uniseriate layers contain 
lamellz of suberin. 
4. Nuclei have been noted, alike in the uniseriate layers in 
which the cell walls and contents are pigmented and in the 
multiseriate layers. These nuclei have been observed in some 
regions in the cells of the eighth layer. 
5. Starch is present in cork cells of all the Rosaceous genera 
