Stomata in Halophytes. 491 
that the calculated surface area of Salicornia shoots is somewhat high, but 
may probably be accurate to within 2-3 %. 
(/ 3 ) Observations on the transpiration of detached shoots during first 
few hours of withering. Through the kindness of Professor Oliver, a num- 
ber of experiments were performed in the field at a salt marsh near Erquy_, 
in the early part of September, 1906. The plants used were a green and 
a red form of Salicornia annua , Suaeda maritima , Atriplex portulacoides , 
and as a control, small plants of Mercurialis annua , which were taken from 
one end of a neighbouring cornfield, to serve as a typical mesophyte. 
Early in the afternoon of September 8, clumps of Mercurialis annua , 
Salicornia annua (both the ‘ apple green 5 and ‘ crimson plain * varieties), and 
of Suaeda maritima were collected from their respective stations, and 
brought to the laboratory. Five shoots of Mercurialis were detached, set 
upright with the stems embedded in a shallow tin of wax mixture, and 
weighed. Ten shoots of each kind of Salicornia were set up similarly, the 
crimson plain shoots being in one tin together, and the apple green in 
a separate tin also together ; and six small plants of Suaeda were placed in 
the same way at a little distance from each other in a fourth tin of wax. All 
the tins were placed in the open, after weighing, and the plants were left to 
wither. The dimensions of the Salicornia shoots were found immediately after 
the first weighing, but the determinations of the surface area of Suaeda and 
Mercurialis shoots had to be deferred until the end of the experiment. Since 
there is undoubtedly shrinkage in the leaves owing to water loss, the area 
estimations will be too low, and the transpiration values per 100 sq. cm. 
correspondingly too high ; but this only emphasizes the fact that the 
halophytes examined had transpiration values comparable with or even 
greater than that of the typical mesophyte, Mercurialis annua. 
TABLE V 
Loss of Weight in Detached Shoots of Mercurialis, Salicornia , and Suaeda. 
Mercurialis. 
Apple Green Sal. 
Crimson Sal. 
Suaeda. 
Hour. 
Time. 
Actual 
Loss. 
Hour. 
Time. 1 
Actual 
Loss. 
Hour. 
Time. 
Actual 
Loss. 
Hour. 
Actual 
Tlme - Loss. 
(1) 
(2) 
(3) 
p.m. 
12.5 
2-35 
4.10 
5-50 
hrs. 
1 
T i 
if 
grm. 
0-075 
0.025 
0-017 
p.m. 
12.10 
2-45 
4.20 
6.30 
hrs. 
2f 
i| 
2 
grm. 
0.106 
0.105 
0.007 
p.m. 
2 
3-30 
5 
6.50 
hrs. 
1 2 
i- 5 
*6 
grm. 
0.058 
0-019 
0-007 
p.m. 
2.1 5 
3-45 
£* 15 
6.45 
hrs. j grm. 
! 
if ; 0.106 
if 1 0-019 
if | 0.024 
Surface Area 
45.14 sq. cm. 
24.43 sq. cm. 
17.44 sq. cm. 
40.38 sq. cm. 
Loss per hour per 
100 sq. cm. 
Loss per hour per 
100 sq. cm. 
Loss per hour per 
100 sq. cm. 
Loss per hour per 
100 sq. cm. 
(1) 
(2) 
(3) 
o-o66 grm. 
0*037 >, 
0.022 „ 
1 0.173 grm. 
jj 0-286 ,, 
;] O.O38 ,, 
0.226 grm. 
0.072 „ 
0.027 » 
0.350 grm. 
0*062 „ 
0.079 „ 
