124 Worsdell. — On the Comparative Anatomy of 
from the strain thus set up, the wall at the point of contact 
of the two cells becomes excessively thickened, and when, at 
length, the final splitting takes place at the middle lamella, 
the retreating portions of the cell-wall appear like drum- 
sticks, owing to their great extension and knob-like swelling 
at the end. The knob often appears as if about to be split 
off from the rest of the cell-wall. In some sections of older 
stems the outermost cells are more contorted and show more 
striking sliding-growth. 
In the ground-tissue of some stems examined occur sac-like 
cells full of dense granular contents. 
On the surface of the stem are scattered a large number 
of mucilage-secreting glands ; each has a stalk of one to three 
cells and a head of secreting-cells about eight in number 
(Fig- 13)- 
The stem bears scale-leaves , which are few in number 
and alternately arranged. They are large as compared with 
the size of the stem on which they are borne, and the upper- 
most bear flowers in their axils. The epidermis of the scale- 
leaf is covered with numerous stomata. These have a very 
irregular arrangement, lying in all directions. As seen in 
surface-view their openings were extremely wide, and their 
guard-cells long and narrow. The subjacent tissue of this 
dorsal surface is exceedingly loose ; the cells are narrow and 
contorted, exhibiting extremely large intercellular spaces ; 
the tissue on the ventral side is more compact, with fewer 
spaces. Mucilage-secreting glands are scattered all over the 
ventral surface. The venation in these organs is to a great 
extent parallel. The bundles have the normal orientation. 
Structure of the Flower . 
The flowers are borne on rather long stalks in the axils 
of bracts. The calyx in this plant is a loose, reduced structure, 
of no definite shape ; it may either terminate in two opposite 
pointed lobes or it may form a mere sheathing body ending 
in an acuminate apex. The anatomical structure of the calyx 
