6 AUSTRALIAN BOTANY. 



in water for several hours, and then examining it, when it 

 will be found larger and heavier — it has commenced to grow 

 or germinate. If left in water for a still longer period, its 

 outer skin will burst, in consequence of the swelling of the 

 seed-leaves. If sown in the ground after having been well 

 soaked, and carefully taken up for examination after several 

 days have elapsed, the plumule and radicle (starting-points) 

 will have become well developed between the cotyledons. 

 The radicle is the first to strike out, growing downwards to 

 form the root. The plumule speedily follows, springing 

 upwards to form the stem. From this time, if undisturbed 

 in the ground, the young plant will make rapid progress. 

 The cotyledons (seed-leaves) will gradually collapse as the 

 growing plant drains them of their substance, until they are 

 quite dried up in the testa, by which time the plant's roots 

 will be vigorous enough to support it. By sowing a number 

 of peas, and taking them up periodically for examination, 

 this operation may be inspected in all its phases. 



Next examine the process of germination or growth in a 

 grain of wheat representing the great class of monocotyle- 

 dons. Unlike the pea, this grain is albuminous (containing 

 albumen). The embryo or future plant is a mere speck in 

 the end of the grain, the rest of the seed-case being filled 

 with albumen for its support during germination. The 

 seed has only one cotyledon or seed-leaf, forming a sheath 

 (covering) around the plumule.' When the embryo com- 

 mences to germinate or grow, it feeds upon the albumen. 

 The great difference between this seed and that of the pea 

 is, that instead of the seed-wheat radicle or young root 

 elongating in a downward direction, thus forming the root, 



