Xll 



INTRODUCTORY LESSONS. 



q h 



a. Section of a seed of Pasonia Brownii, showing the small embryo at the right .m the copious albu- 

 men. 6. The embryo removed and the cotyledons separated, c. The germinating seed. d. The ?ame, 

 with the seed coats removed to show the leaf-like cotyledons, e. Plunmle bud, or real end 01 ne un- 

 ward-growing stem. /. The first plumule leaf as it appears above ground, the terminal bud ye; dormant 

 under ground, g. Seed of Pinus Sabiniana (Digger, Willow, or Nut Pine) soon after it appears above 

 ground, h. Same, with the seed coats removed to show the U cotyledons. See Fig t 9, p. vii 



You must have wondered why the cotyledons of a bean, which 

 never become leaf-like, should appear above ground. It is equally strange 

 that the albuminous seeds of the peony should behave in the reverse 

 way. As shown in the cut (a and b], the embryo is very small. In 

 germination the plumule comes up while the cotyledons become decidedly 

 leaf-like, and fill the shell which has been emptied of its albumen to feed 

 them and the plumule. These thin, veiny seed leaves could certainly do 

 better work above ground than those of most lupines, yet they never come 

 up. There is another curious thing about the growth of peony seeds, 

 which you may try to discover. 



When the buckwheat and cotton seeds have begun to sprout, 

 you can study their embryos. Note how the thin, broad cotyledons of 

 the former are folded once and rolled up with a layer of snow-white 

 starch; and how the speckled seed leaves of the latter are folded along 

 the center, then outwardly back, and finally crumpled endwise to make 

 them fit coats too short for them. Maple seeds have curiously crampled 

 and folded cotyledons. Indeed, all seeds have interesting lessons to 

 teach us. 



Germination of Monocotyledonous Seeds. The seeds named 



