22 FAMILIAR LESSONS IN BOTANY. 



47. Lenticels are the spots, mostly of brownish color, 

 found on the surface of cherry and other trees. 



48. The Bark is beneath the epidermis, and consists of 

 several layers. 



49. During its early stages it presents a uniform struc- 

 ture, and is entirely cellular ; but as the tree advances, 

 lactiferous vessels and woody fiber are introduced into the 

 inner portion, which is called liber. Here is obtained the 

 fiber of flax, hemp, and ramie, which furnish to the manu- 

 facturer materials for the gossamer laces of Brussels and 

 Valenciennes, as well as all the gradations from these 

 down to carpets, sail-cloth, and bagging. From the liber 

 of some plants a beautiful paper is obtained, and the 

 natives of the South Pacific isles procure a lace of exquisite 

 texture from the inner bark of one of their forest-trees. 

 Before leaving the subject of the inner bark, I will men- 

 tion the fact that the substance of which it is composed, 

 woody fiber, is remarkable for its indestructibility by decay. 

 You may take the linen that has lain in a Theban tomb 

 three thousand years, grind it to a powder, and boil it to a 

 pulp, and the manufacturer will present it to you again, in 

 a week, in the form of paper for your letters, or bound in a 

 volume to become the custodian of the mental labors of a 

 Humboldt or the songs of a Tennyson. 



50. The outer layer of the bark is called cellular integu- 

 ment. It varies in thickness in different plants. The 

 QuERCUS suber, cork-tree, has it prodigiously developed, 

 and furnishes thereby the cork of commerce. It is not so 

 useful to man as the liber or inner layer, yet, besides the 

 very important contribution already mentioned, we are 

 indebted to it for many esculent roots, which by cultiva- 



47. What are lenticels? Where seen ? 



4 8 . Where is the bark situated ? Of what does it coneipt ? 



49. Where is the liber? What is obtained from it? What is the outer layer 

 called ? 



50. What tree has this integument largely developed ? What are the offices of 

 the bark ? Tell me some of the substances found in the bark. 



