THE STEM AND BRANCHES. 161 



Finally, when the seed is put into the ground 

 and exposed to warmth and moisture, it begins to 

 germinate. This it does by sending up a small 

 growing shoot towards the light, which soon de- 

 velops green leaves; as well as by sending down 

 a root towards the earth, which soon begins to 

 suck up water, together with the dissolved nitroge- 

 nous matter. That is the beginning of a fresh 

 plant-colony, which thus owes its existence to two 

 separate individuals, a father and a mother. The 

 seed consists of two first seed-leaves in the five- 

 fold plants, as you can see very well in a sprout- 

 ing bean, and of one such seed-leaf in the three- 

 fold division, as you can see very well in a sprout- 

 ing grain of wheat, or, still better, a lily seed. 

 These earliest leaves are technically known as 

 seed-leaves or cotyledons, and that is why the five- 

 fold plants are known to botanists by the awk- 

 ward name of dicotyledons, while the threefold are 

 called monocotyledons. These names mean merely 

 plants with two or with one seed-leaf. 



CHAPTER XII. 



THE STEM AND BRANCHES. 



You may have observed that so far I have 

 told you a good deal about leaves and roots, flow- 

 ers and seeds, but little or nothing about the na- 

 ture of the stems and branches that bear them. 

 I have done this on purpose; for my object has 

 been to give you as much information at a time 

 as you could then and there understand, building 

 up by degrees your conception of plant economy. 



