Delf. — Transpiration in Succulent Plants. 41 1 
In the case of Suaeda and S at sola the method employed was that described 
in my paper on ‘ Transpiration and Behaviour of Stomata in Halophytes ’ 
(‘Annals of Botany’, xxv, p. 487); for Salicornia the micrometer screw 
method detailed in the same paper (p. 487) ; whilst the small leaves of 
M esemhryanthemum crystallinum were estimated both by the micrometer 
screw and celluloidin method, 1 and the mean between the two determina- 
tions (which usually differed by from 1-3 per cent.) taken as a fair 
approximation to the true surface area. In all cases the stem was included 
in the determinations both of areas and of dry weights. 
The succulence of the leafy shoots of Salsola Kali and Arenaria pep- 
hides is probably somewhat underestimated, for the only material available 
had been sent by post from some distance, and although kept in water for 
some time before using were probably not fully turgid at the time of the 
experiment. The shoots of the remaining examples were obtained direct 
from healthy plants cultivated in the garden at the James Allen’s Girls’ 
School, Dulwich, 2 where there is an artificial salt-marsh, which is watered 
at intervals with a 1-2 per cent, solution of Tidman’s sea-salt, and also an 
artificial sand-dune, and pebbly sea-shore, in a very flourishing condition. 
It was ascertained, by means of the thallium sulphate test, that the plants 
used had a very considerable salt content, but they probably show a some- 
what less succulence than that of plants in their natural habitat, especially 
in the case of variable plants, such as Aster Tripolium and Arenaria 
pep hides? 
Table I. 
Water Content per sq. dm. in some typical Succulent and 
Mesophytic Plants. 
Plant. 
Water 
Content %. 
0 Water Content in 
Pla srm.persj.dm 
( ‘ Degree of succulence . ) 
Mesembryanthemum edule . . . 
96.3 
4 
12*6 
„ crystallinum 
97.7 
3.28 
6.2 
Suaeda mariiima 
9°*3 
40.38 
10*0 
-< Salsola Kali 
86-6 
17-16 
6.9 
Salicornia annua 
89*0 
24-43 
6-5 
Arenaria peploides 
89.2 
12*34 
5*5 
Plantago maritima 
95- 2 
84.76 
4 .8 
1 Aster Tripolium 
9 I *5 
92.18 
3*7 
I Sedum Sieboldii 
93.6 
26-87 
3-4 
J A triplex portulacoides . . . . 
88.9 
54-H 
3*3 
| Cakile maritima 
91-8 
14.96 
2.8 
Eryngium maritimum . . . . 
85.0 
90.72 
2-5 
K Glaucium 
89-0 
46.50 
2-1 
Statice Limonium ..... 
81.2 
I 4 I, 7 8 
i-7 
- Saponaria officinalis ..... 
78.4 
82.28 
i-4 
Mercurialis annua 
77-o 
45* I 4 
o*95 
1 Delf, E. M. : Loc. cit., pp. 488, 489. 
2 By kind permission of the Head Mistress, Miss Howard ; and of Miss L. J. Clarke, the senior 
Science Mistress, in whose laboratory these determinations were also made. 
3 Cp. Lesage, P. : Recherches experimentales sur les modifications des feuilles chez les plantes 
maritimes. Revue Gen6rale de Botanique, 1890. 
