6 Introduction to Botany. 



x 1.5 ; that is, the diameters of the drawings are to be 1.5 

 times as great as the corresponding diameters of the bean. 

 The two most important points of view are those which 

 best show the form of the bean, and the structures which 

 may have some significance in the formation or germina- 

 tion of the seed. If beans in the pod, preserved in 2% 

 formalin, or in 70% alcohol, are available, the data for 

 judgment will be more complete. Compare with the dry 

 bean one which has been soaked in water over night, and 

 note any difference in size, form, and texture. 



2. Slip the skin or seed-coats (there are usually two 

 seed-coats, the outer, termed the testa, being thicker and 

 harder than the inner) carefully from a soaked seed, notic- 

 ing whether it is attached to the rest of the seed at any 

 point, or simply lies in contact with it. Can any structures 

 be seen after the seed-coats are removed which could not 

 be seen before ? If so, make drawings from the two points 

 of view which will most clearly show them. Is there any 

 connection between structures which are removed with the 

 seed-coats and those lying beneath them ? How do the dry 

 and soaked seed-coats of the bean differ as to hardness 

 and toughness ? What significance do you see in the differ- 

 ence ? In what ways is the seed protected against injury ? 

 Answer these questions in the notes, and refer to the draw- 

 ings wherever they will illustrate what is said. 



3. After the seed-coats have been removed, note whether 

 the two halves of the bean, termed cotyledons, are united 

 at any point; then carefully separate the cotyledons and 

 place them on the table, convex side down, and in contact, 

 at the right point, with any part from which they may 

 have been severed. Draw as thus seen on the same scale 

 as before. 



4. Study with a lens the structures which were revealed 



