LESSON 3.] GROWTH OP THE PLANT FROM THE SEED. 



15 



the albumen, or white of the egg, which encloses the yolk, and 

 therefore gave it the same name, the albumen of the seed, a 

 name which it still retains. Food of this sort for the plant is also 

 food for animals, or for man ; and it is 

 this albumen, the floury part of the seed, 

 which forms the principal bulk of such 

 important grains as those of Indian Corn 

 (Fig. 38 - 40), Wheat, Rice, Buck- 

 wheat, and of the seed of Four-o'clock, 

 (Fig. 36, 37), and the like. In all 

 these last-named cases, it may be ob- 

 served that the embryo is not enclosed 

 in the albumen, but placed on one side 

 of it, yet in close contact with it, so 

 that the embryo may absorb readily 

 from it the nourishment it requires 

 when it begins to grow. Sometimes 

 the embryo is coiled around the outside, in the form of a ring, as 

 in the Purslane and the Four-o'clock (Fig. 36, 37) ; sometimes it is 

 coiled within the albumen, as in the Potato (Fig. 34, 35) ; some- 

 times it is straight in the centre of the albumen, occupying nearly its 

 so 32 34 ss whole length, as in 



the Barberry (Fig. 

 32, 33), or much 

 smaller and near one 

 end, as in the Iris 

 (Fig. 43) ; or some- 

 times so minute, in 

 the midst of the al- 

 bumen, that it needs 

 a magnifying-glass to 

 find it, as in the But- 



37 



FIG. 29. Germination of the Morning Glory more advanced : the upper part only ; showing 

 the leafy cotyledons, the second joint of stem with its leaf, and the third with its leaf just 

 developing. 



FIG. 30. Section of a seed of a Peony, showing a very small embryo in the albumen, 

 near one end. 31. This embryo detached, and more magnified. 



FIG. 32. Section of a seed of Barberry, showing the straight embryo in the middle of 

 the albumen. 33. Its embryo detached. 



FIG. 34. Section of a Potato-seed, showing the embryo coiled in the albumen. 35. Its 

 embryo detached. 



FIG. 36. Section of the seed of Four-o'clock, showing the embryo coiled round the 

 outside of the albumen. 37. Its embryo detached- 



