6 ELEMENTS OF BOTANY. 



Notice the presence of a distinct plumule, consisting of a pair of 

 rudimentary leaves between the cotyledons, just where they are joined 

 to the top of the caulicle. 



Make a sketch of these leaves as they lie in place on one of the 

 cotyledons, after the bean has been split open. 



Note the cavity in each cotyledon caused by the pressure of the plumule. 

 ' Place that cotyledon from which the sketch was made on the stage of the 

 compound microscope under the lowest-power objective which the micro- 

 scope has (say 2-inch), with light thrown on the object from above, and 

 sketch the plumule as thus shown, i 



4. Examination of the Pea. — There are no very important points of 

 difference between the bean and pea, so far as the structure of the seed is 

 concerned, but the student should rapidly dissect a few soaked peas to get 

 an idea of the appearance of the parts, since he is to study the germina- 

 tion of peas in some detail. 



Make only one sketch, that of the caulicle as seen in position after the 

 removal of the seed-coats. ^ 



5. Germination of the Bean and the Pea. — Soak some beans as directed 

 in § 3, plant them, and sketch as there directed. 



Follow the same directions with some peas.^ 



6. Germination of the Horse-Chestnut. — Plant some seeds of the horse- 

 chestnut or the buckeye, study their mode of germination and make out 

 the nature and peculiar modifications of the parts. 



Consult Gray's Botanical Text-Book, vol. I, pp. 19, 20. 



7. Conditions Requisite for Germination. — When we try to 

 enumerate the external conditions which can affect germinar 

 tion, we find that the principal ones are light^ heat, moisture, 

 and presence of air. A few simple experiments will show 

 what influence these conditions exert. 



8. Experiment 1.^ (a) Does Light assist Germination? {h) Does 

 Light retard Germination ? — Put a piece of blotting-paper in the bottom 



• The teacher should at this point give a short illustrated talk to explain in a 

 general way the construction and use of the compound microscope. See Appendix A. 



2 The teacher will find excellent sltetohes of most of the germinating seeds 

 described in the present chapter in Miss Newell's Outlines of Lessons in Jiota/ny, 

 Part I, and in Gray's Lessons in Botany. 



' The pupil may economize space by planting the new Seeds in boxes from which 

 part of the earlier -planted seeds have been dug up for use in sketching, etc. 



* This may readily be made a home experiment. 



