2S8 



General Botany 



U. S. Dept. oj Agriculture 



Fig. i66. Coffee berries, natural size. Each contains two seeds. 



thick and contain a great supply of food. The bean is an example 

 of a large group of plants, including the pea, squash, apple, and 

 pumpkin, in the mature seeds of which the endosperm is lacking. 



A grain of corn is an example of a third kind of seed. In it 

 there is a large endosperm, with a small embryo near one end of 

 the seed. The embryo differs from the embryos of the bean and 

 the castor bean in that it has only a single cotyledon, wrapped 

 more or less around the hypocotyl and plumule. The plumule 

 grows upward and forms the aerial shoot. As in the castor 

 bean, the cotyledon is the absorbing organ through which the 

 foods in the endosperm enter the young plant, but in the corn 

 the cotyledon is not forced out of the soil by the elongation of the 

 hypocotyl. 



The flower and embryo in monocots and dicots. In discussing 

 the subject of stems, attention was called to the fact that flowering 

 plants are divided into two great groups, the monocots and dicots. 

 The monocots have parallel-veined leaves ; the bundles of the 

 stem are closed (have no cambium) and are not arranged in a 

 circle. 



The terms '^monocot" and "dicot" (or, as they are frequently 

 written, ''monocotyledon" and ''dicotyledon") are based on 



