130 



not interfere with their photosynthesis. But the cuticle is 

 strongly developed, and intercellular spaces are very inconspic- 

 uous in the leaf. As the plants grow taller the leaves are more 

 of the time above water, and are stiff enough so that many of 

 them stand erect above the surface, but when too great a length 

 is exposed they float. Free movement of gases, when the leaves 

 float or are submerged, is insured by the position of the stomata. 

 These occur only on the upper surface of the leaves, where they 

 are confined to the sides of deep and narrow clefts. The walls 

 of these clefts are beset with papillse, which further narrow them 

 and increase their surface until it is practically impossible that the 

 air in them should be driven out by water. The stomata being 

 protected against plugging by water, the plants continue to take 

 up carbon dioxide though entirely under water (Cf. Pfeffer, 

 Pflanzenphysiologie, I: 161, 2d ed.). As must be expected, 

 especially from Stange's work (Bot. Zeit. 1892), the plant meets 

 the concentration of the sea water with an over-regulation of its 

 turgor. In the mesophyll, in a leaf reaching above high tide, 

 I have found plasmolysis just beginning in 7.5 per cent. KNO ; 

 in the cortex of the roots, in 7 per cent. KNO. I could find no 

 root hairs. 



SHORTER NOTES 



Weeping Tomatoes. — Some days after clearing off a plot of 

 ground in tomatoes for the past season it was observed that the 

 places where the plants had stood were moist while all the other 

 area was covered with the dry, finely raked earth. Upon examina- 

 tion it was found that this moisture was due to water that flowed 

 from the roots of the tomato plants that had broken off and re- 

 mained in the soil in the process of pulling. Further inspection 

 showed that when a broken end of one of the larger roots chanced 

 to extend above the soil its exposed fraction was wet and dripped 

 water so that it glistened in the late October sun. From some 

 roots that arched over with the broken end pointed downward 

 the water fell in drops to the soil which was literally muddy be- 

 low the live spigot. 



Having other plots to clear, many of the tomato plants were 



