A TEXTBOOK OF BOTANY 



CHAPTER I 

 A BRIEF STUDY OF A FAMILIAR PLANT 



The Squash, Pumpkin, or Cucumber* 



1. The Squash Seed (Fig. i). — This is a hard, fla,t, white 

 object, rounded at one end and more or less pointed at the 

 other. At the pointed end is a scar marking the part of the 

 seed by which it was attached to the inside of the fruit (which 

 we commonly call the " squash ")• In this scar and a little 

 to one side of the point is a conspicuous depression or hole, 

 the micropyle. If a seed has first been soaked overnight, 

 it is easier to remove the outer hard covering, the seed coat. 

 Just inside this is a thin, greenish, skin-like layer, the en- 

 dosperm. Within this is the embryo, or young plant, which 

 makes up the larger part of the seed. One end of the embryo 

 is rather pointed and is called the radicle; this is turned 

 toward the micropyle. The greater part of the embryo is 

 made up of two thick seed leaves, in which food is stored that 

 is to be used by the embryo when the seed germinates. The 

 seed leaves are attached to the radicle, and between the seed 

 leaves, at the point where they join the radicle, is a small 

 swelling, the plumule. The plumule bears two very small 

 secondary leaves, which, however, can hardly be made out by 



1 Although any one of the three plants mentioned may be used for the work of 

 the present chapter, the cucumber will usually be found most convenient because 

 of its smaller size. But the cucumber seed is not so favorable for study as is the 

 larger seed of the squash or pumpkin. Specific reference is made, therefore, to the 

 seed and seedhng of the squash, and to the mature plant, flowers, and fruit of the 

 cucumber. 



I 



