Roots of Some Rosaceous Genera. 55 
walls, between which intercellular spaces are formed, together 
with occasional compact layers of cells with a suberized zone.” 
The points presented in this paper will be given under the 
following headings : 
(az) Intercellular spaces and annular arrangement of cell 
layers. 
(4) Suberization of the periderm. 
(c) Presence of nuclei in cells of the cork region. 
(dz) Starch in the cork region. 
(e) Pigment of the cork region. 
(7) Comparison of root and shoot. 
(g) Evidence as to the relative evolutionary position of the 
Rosaceous groups. 
(4) Summary of results. 
(a) Intercellular Spaces and Annular Arrangement of Cell 
Layers——tThe following groups of the Rosacee have been 
studied, with a view to solving the problem of the presence or 
absence of intercellular spaces, with the appended results: 
Group Potentillee.—Ten species of this group have been 
studied, viz.: P. norvegica, P. chrysantha, P. alpestris, P. geoides, 
Geum atrosanguineum, G. album, G. nutans, G. triflorum, Fra- 
garia indica and Waldsteinia geotdes. All the above species 
of this group have been observed to contain intercellular 
spaces, which are quadrangular in shape. A _ noticeable 
character of the cork region of this group is the annular 
arrangement of the cell layers. These may be arranged 
according to three types: First, alternating layers of cells of 
different sizes as in Geum album ; second, alternating uniseriate 
layers of cells whose cavities contain pigment, and of cells 
devoid of pigment contents, as in Waldsteinia geoides ; third, 
uniseriate layers of flattened compact cells, with deeply 
pigmented cell walls whose cell cavities contain a brown 
pigment, alternating with less compact multiseriate layers 
which contain no pigment within the cell cavities, but which 
may sometimes have their walls pigmented, especially in the 
