YAMS, COCOES, AND SWEET POTATOES. 165 
YAMS, COCOES, AND SWEET POTATOES.— 11 
1. Mr. Hill next spoke to the boys about the 
veins in the leaves. 
''All the three food-plants of which we are 
talking have net-veined leaves/' he said. " I 
speak of that because it is odd that the yam and 
coco should have such leaves. They belong to 
the great class of plants with one seed-leaf, and 
those plants, like the corn, usually have their 
leaf-veins side by side, as I think you already 
know." 
2. Mr. Hill then told the boys that although 
some cocoes have their leaves green, and others 
rather purple, the tubers of both kinds are alike. 
He showed them, too, that the chief kinds of 
sweet potato may be known by the leaf, which 
is round and in one piece in the white kind, and 
parted into lobes in the red. 
3. When they asked about the different kinds 
of yams he said: ''There are the white, negro, 
afou or yellow, and Indian yams. The last, also 
called Yampi or Yampee, has its leaf in three 
leaflets, and bears small round tubers, which are 
generally white inside, but sometimes of a deep- 
purple colour; the others have heart-shaped 
leaves, and very large white or yellow tubers. 
4. "You saw the men planting some yams a 
