502 
Delf \ — Transpiration and Behaviour of 
both in the outward and downward direction when the pore opens, and 
conversely, the total diameter and the depth of the guard cells diminishes 
on closing : most commonly the rift is still obvious when the pore appears 
to be completely closed. 
In September, October, and November, 1910, fresh material of Salt - 
cornia annua from various sources was examined for stomata. In some 
plants obtained from Burnham-on- Crouch in late September, the stomata 
were all closed and did not open when placed in either a damp or dry 
Fig. 12. Outline drawing of stomata of Salicornia annua in the half-open and closed condition 
respectively, seen in surface view from above, x 500. 
Fig. 13. Outline drawing of stomata of Salicornia annua in the half-open and closed condition 
respectively, but seen in cross-section, x 500. 
atmosphere, with sunlight or bright diffuse light. The guard cells appeared 
to be turgid, but no opening was visible, and even when a strip of epidermis 
was mounted in water and exposed to bright diffuse light, only a narrow 
slit-like opening appeared. These plants were in their flowering period. 
Other plants from Cley, received early in October, bore young seeds, 
and the stomata on these shoots behaved similarly ; whilst material from 
Southampton later in the same month, and from Rye early in November, 
bore stomata which were all closed, and which seemed to have entirely lost 
the power of movement. It thus appears that in Salicornia annua , and 
presumably also in other annual species of the same genus, the stomata 
begin to lose their capacity for movement during the flowering season, and 
finally remain permanently closed. 
The stomata of Aster tripolium are found on both sides of the leaf ; 
they are from four to five times larger than those of Salicornia annua , 
