SEEDS AND SEEDLINGS. 



47 



apart when ripe, but for a time dangle at the ends of a 

 Y-shaped thread whose lower end is attached to the top of 

 the flower-stalk. 



Open a ripe key, noting the hairs inside the shell; the 

 brown-coated seed; the embryo with its long radicle, long 

 strap-shaped green cotyledons, and very small plumule ; the 

 stages of germination, in which the cotyledons are carried 

 up and unfold, while the plumule grows very slowly; the 

 simple outline of the earliest foliage-leaves (Fig. 24). 



Fig. 24. Sycamore. A, fruit; B, with the half -fruits ("keys") split apart; C, D, 

 views of embiyo ; E, " key" opened up, showing seed ; P, seedling with the first 

 two foliage-leaves. 



Get ripe Sunflower "seeds," also Sunflower heads of 

 different ages showing flowers and developing fruits, noting 

 the scar left at the broad end of the akene where the 

 upper parts of the flower fell off; the scar (often a hole) 

 at the lower pointed end of the akene where it became 

 detached from the plant ; the seed, attached by a short stalk 

 inside the shell; the thin seed-coat, the cotyledons, radicle, 

 and small plumule. Test cut surface of a cotyledon with 



