202 ROOTS. 



cold that has such an effect. Those who convey seeds from dis- 

 tant countries, should be instructed to keep them dry ; for if 

 they receive any damp sufficient to cause an attempt at vege- 

 tation, they necessarily die, because the process cannot, as they 

 are situated, go on. It is usual with gardeners to keep melon 

 and cucumber seeds for a few years, in order that the future 

 plants may grow less luxuriantly, and be more abundant in 

 blossoms and fruit. Dr. Darwin accounts for this from the 

 damage which the lobes may receive from keeping, by which 

 their power of nourishing the infant plant, at its first ger- 

 mination, is lessened, and it becomes stinted and dwarfish 

 through its whole duration. 



Questions. — 1. What takes place when a seed is committed to the 

 ground? 2. What is said of the young root ? 3. Of sea-weeds? 4. 

 Of Dodder ? 5. What are the two lobes called ? 6. The germ ? 7. 

 How do the leaves of the germ assist the plant ? 8. To what use is the 

 farina of the lobes applied ? 9. What are plants called that have only 

 one lobe ? 10. What is said of the preservation of the vital principle 

 in see^? ? 11. Why do gardeners sometimes keep melon and cucum- 

 ber seeds for a few years ? 12. How does Dr. Darwin account for this ? 



LESSON 91. 



Roots, Ste7ns, Buds, and Leaves. 



Rad'icle, the minute branch of a root. 



Physiology, the doctrine of the constitution of the 



nature. 

 Pcrs]>ire', to give out moisture. Absorb', to take in moisture* 



The root of a plant consists of two parts, the body of 

 the root, and the fibre. The latter only is essential, being 

 the part which imbibes nourishment. Roots are either of 

 annual, biennial, or perennial duration. The first belong to 

 plants which live only one year, or rather one summer, as 

 barley; the second to such as are produced one season, and, 

 living through the ensuing winter, produce flowers and fruit 

 the following summer, as winter-rye and wheat ; and the third 

 to those which live and blossom through many succeeding 

 seasons to an indefinite period, as trees and many herbaceous 

 plants. Botanists distinguish several different kinds of roots, 

 which are necessary to be known, not only for botanical 

 purposes, but as being of great importance in agriculture and 



