Holtz -: OBSERVATIONS ON PELVETIA. 4.3 
DESCRIPTION OF PLATES. 
lesoy oe WAU 
Photograph of single plant of Pelvetza fastigiata. Shows hold- 
fast, bifurcation of stipe and of lamine. The warty appearance of 
some older laminz is due to papille caused by conceptacles. Several 
lamine have burst open through absorption of water, and show the 
conceptacles on the inner side of the cortex. About one half natural 
size. 
Peace Vine 
Photograph showing bed of Pelvetza fast¢gzata on the rocks at Port 
Renfrew, exposed at ebb tide. This photograph was taken by C. J. 
Hibbard for the Botanical Department of the University of Minnesota. 
Brame It: 
Anatomical detail: All drawings were made with the aid of camera 
lucida, diagrams excepted. AlIl on this plate about x 250. 
1. Shows part of the cross-section of stipe from epidermis to center 
of stipe. 
2. Longitudinal section of stipe, showing cells with protoplasm, 
nuclei and chromatophores. The protoplasmic connection between 
ells is indicated. The cuticle covers the epidermis. 
3. Cross-section of lamina. Shows the large amount of intercel- 
lular jelly in the pith region. 
4. Longitudinal section of lamina, showing anastomosing pith cells. 
The space between them is filled with intercellular jelly. 
5. Diagram of longitudinal and cross-section of stipe or lamina. 
Shows radially elongated epidermal cell. Beneath this are six or 
more rows of cortex cells and beyond these the pith. The cortex is 
shown arising as a basal cut-off of the epidermis. Previous cut-offs 
are shown in different stages of growth and division. Growth is prin- 
cipally in periclinal and longitudinal directions. The outer cells are’ 
more regularly rectangular, but become more rounded on the edges 
and corners toward the pith. The inner cortex rows finally become 
modified into long, cylindrical pith cells. The cells are separated 
farther by intercellular jelly as the pith is approached. 
6. Vertical section through central part of holdfast. The lower 
part is shaded to show that the cells are dead, elsewhere also where 
such cells occur. ‘The basal cells are flattened. The walls of the dead 
cells are gelatinous. The cells are shown with chromatophore masses 
to help indicate division. Inthe upper part the cells are elongated. 
Here the stipe begins. 
