'LABORATORY PRACTICE 



" '5*. *TRe*sho*rf *ridge*(ase the lens) running from it toward 

 one end of the seed. This ridge (called the rhaphe} 

 runs from the hilum along upon the outside of the seed 

 for a short distance, and then penetrating through the 

 coverings of the seed, disappears into the interior. 

 That portion of the rhaphe next to the hilum is 

 covered, in the Bean, by the strophiole. 



6. The small hole at the side of the hilum just opposite the 



strophiole. This is the micropyle, and is usually 

 readily seen by the aid of the lens. If the surface 

 of the seed is dried carefully, water may be made 

 to ooze out of the micropyle, if the Bean is gently 

 squeezed. This shows that the hole extends through 

 the coats or coverings of the seed. 



7. Sketch the Bean in such position as to show all of these 



parts, and label each distinctly. 



III. With a scalpel or sharp penknife, make a cut along 

 the edge of the Bean opposite the scar. 



1. Remove the seed-coats. There'are really two seed-coats, 



but they are so firmly united in the Bean as to be 

 inseparable. The strophiole comes away with the 

 seed-coats, for it is really a rudimentary third coat. 



2. It will be noticed that the seed-coats are not attached to 



the contents (or kernel) of the seed except at one 

 point, which is just under the place where the rhaphe 

 penetrates the seed-coats. This point is called the 

 chalaza. It is somewhat difficult to demonstrate, but 

 if one takes a dry Bean (of the small white variety, 

 commonly used for baking), and cuts out a crescent- 

 shaped piece on the hilum side, taking care to include 

 the free end of the rhaphe, one or both pieces of the 



