270 THE EFFECT OF MOISTURE 



Changes in the epidermis were much less frequent, 

 there being no appreciable difference in 31 plants. In. 

 23 of the shore plants the cells were larger, however, 

 they being three to five times as large in Beta vulgaris 

 and Silene maritima. In four instances these cells 

 were larger in the inland plants. With regard to the 

 chlorophyll, there was no difference in some cases, but 

 in others it was marked. Thus in Thesium humifusum 

 and CaJcile maritima the grains were much smaller in 

 the maritime plants, and in other species the number of 

 grains was reduced. 



Even more conclusive evidence of the direct effect of 

 salinity in producing these peculiarities of structure 

 has been afforded by experiment. Lesage cultivated 

 various plants under similar conditions except that 

 some of them were watered with water containing com- 

 mon salt, and he found that characters were developed 

 similar to those exhibited by maritime plants. In 

 Pisum sativum the leaves increased in thickness, pali- 

 sade cells became larger and more numerous, whilst the 

 intercellular spaces and the chlorophyll diminished. 

 Lepidium sativum (Garden Cress) gave even more 

 marked results. The palisade tissue was more devel- 

 oped and possessed an extra layer; the lacunae were less 

 pronounced, and the chlorophyll less abundant. On 

 sowing the seeds of this plant a second year, moreover, 

 and again treating the plants with salt water, a still 

 more marked result was obtained, it appearing as if the 

 alteration in the tissues of the second generation was 

 carried on more or less from the point gained in the 

 first. The salted water might even affect physiological 

 processes. Thus radishes usually contain no starch, 



