OR, PLAIN TEACHING. 



197 



554. 



and the majestic oak, 572, of the 

 forest.* 



The roots and the stems of 

 plants grow in contrary direc- 

 6 tions ; the 



8 first de- 

 scend into 

 the earth, 

 while the 

 second 

 ascendinto 

 the atmo- 

 sphere. 

 10 Vertical 

 roots, 6, 

 are those 

 which sink 

 p e r p e n- 

 dicularly into the earth, as the 

 carrot, 7, the turnip, 8. They 

 are not true roots, however, but 

 give off fibrils, 9, 10, which are 

 the proper roots. 



Fibrous roots, 11, are those that 

 n give off 



a great 

 number 

 of fibres, 

 which 

 are ei- 

 ther sim- 

 ple and 

 slender, 

 12, or 

 thick and ramified, 13. 



Tuberous plants, 14, have at- 

 tached to the creeping under- 

 ground stem, tubers, or roundish 

 bodies. These tubercles, 15, or 

 fleshy bodies, which are com- 

 monly, but erroneously, called 

 roots, are masses of a starchy 

 substance, which nature has thus 

 stored up to afford a supply of 

 nutritious matter for the future 



* ilhmd's History of the Vegetable Kiugdom. 



555. 



germ. They are more or less 

 numerous, as in the Jerusalem 

 artichoke, and the potatoe. 



556. 



The tuber of the potatoe is an irregular en- 

 largement of the creeping under-ground stein. 

 The tubers of the same plant are all connected 

 together, and to the parent stem, by single 

 bands of small diameter, consisting chiefly of 

 woody fibre, for the purposes of the circulation of 

 the plant. The precise manner in which the 

 tube enlarges is unknown ; but it is quite clear 

 that it must be freely supplied with circulating 

 juices from the stem. This is effected by the 

 woody fibre, and bundles of it ramify within the 

 tubes, and pass to each growing point.* 



The bulb, as of the onion and 

 the lily, 15, is also an under- 

 ground stem, in the rudimentary 

 state of a leaf-bud. It is a fleshy, 

 conical body, with scales, 16, 



557. 



surrounding a growing germ, 17, 

 and emitting roots, 18, from its 

 base. These are the principal 

 forms of roots ; but there are 

 many modifications and varieties. 



• Orr'a Circle of the Sciences. 



