4.14 WALTER GARDINER. 
the apex soon withers and the gland becomes destroyed. 
Thus, in very young barley plants (Hordeum vulgare) large 
drops of water may be seen hanging on the apex of each 
leaf, even though the temperature of the surrounding air be 
as much as 74° Fahr. As they grow older the secretion 
stops, and later on each leaf-apex withers up and dies. 
