LEAVES. 
91 
8. "I wonder what makes this tobacco leaf so 
rough/' said Jane, as she passed her fingers over 
the surface of the large leaf. 
It is covered with stiff' hairs/' said her father. 
How different it is from this smooth, shiny 
orange leaf Many leaves have hairs : some, like 
those of the aloe, pine-apple, and pinguin, have 
sharp spines at their edges, and are very stiff* and 
thick." 
4. " That is why the pinguins make such a 
good hedge when they are planted in a row," said 
Frank. 
You have not told us anything about these 
lines in the leaves," said Jane, as she pointed to 
the ribs in a young banana leaf. 
5. We will not leave them out, Jane," said 
her father, '^for they are very important. They 
are called the veins or the of the leaf. They 
make a strong framework by which the blade is 
spread out, just as the ribs of an umbrella support 
the silk or cotton. Besides, they carry to the 
green cells of the leaf the plant-food that has 
been drawn up from the soil." 
6. " See what a thick rib the middle one is," 
said Frank. 
''Yes; that is called the mid-inb. It gives 
strength to the leaf In some leaves, as in that 
cocoa or chocolate leaf, the veins spread about 
