BY SELF-ADAPTATION TO THE ENVIRONMENT. 231 
in an exposed heated spot, to be more or less cylindrical. 
M. Battandier also says that two other species which are not 
rupicolous but grow in dry earth, viz. Sedum rubensand S. Magnoli, 
have flat leaves in a wet season but cylindrical leaves in a dry one. 
Similarly the common maritime fleshy Samphire of temperate 
climates, Crithmum maritimum, when cultivated in a garden 
became luxuriant and bore flat and smooth leaves. 
Centaurea crassifolia, a plant peculiar to the Maltese islands, 
growing in hot rocky valleys, has thick succulent leaves which 
survive during the hot season; but in March, when it begins to 
produce its new foliage, before the hot summer has approached, 
I found that the leaves were nearly as thin as in ordinary plants. 
As another example, M. Costantin observed * that Salsola 
Kali, a common inhabitant of maritime salt marshes, grows up 
sandy rivers, when it passes into S. Zragus by losing its fleshy 
leaves. 
The most elaborate series of experiments to test the source 
of the succulency of the maritime plants has been carried out 
by M. Lesaget, who shows conclusively that the presence of 
salt is at least a potent cause in its production. He succeeded 
in making plants, such as garden cress, succulent by watering 
with salt water. He also testifies to the hereditary effect, in 
that seed obtained from plants of cress which were somewhat 
succulent in the first year’s experiment became still more so in 
the following. 
The increased substance of the leaf is accompanied by a 
greater development of palisade-tissue with diminished inter- 
cellular passages and a less proportion of chlorophyll. This 
latter result is correlated with a relative decrease in the amount 
of starch produced. 
From all the above facts, natural and experimental, the 
conclusion is inevitable that while succulency is of benefit to the 
plants under the conditions in which they grow, especially by 
enabling them to store water during the hot and dry season, it 
is in all cases actually brought about by the direct action of the 
environment itself, coupled with the responsiveness of the pro- 
toplasm of the plant. 
* Journ. de Bot., 15 mars 1887. - 
t Rev. gén. de Bot. vol. ii. pp. 55, 106, 163; see also Comptes Rendus, cxii. 
1891, p. 672. 
