102 BOTANY FOR BEGINNERS CHAP, vin 



SUMMARY. 



Parenchyma cells are those in which the diameter is about the same 

 in all directions. 



Prosenchyma cells are long and narrow. 



Vessels are formed by the perforation of the transverse walls of cells 

 which are placed end to end. The following are very common : 

 Spiral vessels. Reticulate vessels. 



Annular vessels. Pitted vessels. 



Sieve tubes are formed from cells which have their transverse walls 

 perforated to form sieve plates. 



Tissues. There are three tissue systems in a plant, viz. : 



Epidermal tissue, which covers and protects the deeper parts of 



the plant from injury. 

 Vascular tissue, which forms the supporting and conducting tissue 



of the plant. 

 Ground tissue, which fills in the spaces between the epidermal and 



vascular tissue. 



Stomata are the small openings which are found between guard -cells 

 in the epidermis of the aerial parts of plants. 



Hairs may be either unicellular or multicellular. They may protect 

 the plant from insect pests, or be used for taking in food. 



Vascular bundles may be closed or open. If the bundle is open it 

 will consist of ( I ) Xylem ; (2) Cambium ; (3) Phloem. 



If the bundle is closed it will consist of (i) Xylem, and (2) Phloem. 

 The Course of Vascular Bundles depends upon the arrangement 

 of the leaves on the stem. 



QUESTIONS ON CHAPTER VIII. 



1 i ) How does a parenchyma cell differ from a prosenchyma cell ? 



(2) What is a vessel? How are vessels formed? Enumerate the 

 different kinds which are found in wood. 



(3) In what respects of structure and function do the vessels of the 

 bast (sieve tubes) differ from those of the wood ? (1892.) 



(4) Describe fully the structure of a vascular bundle in the stem of a 

 dicotyledon. Explain how such a bundle differs from that of a mono.- 

 cotyledon. (1894.) 



(5) What is a stoma? On what parts of the plant are the stomata 

 chiefly developed ? How is a stoma formed ? 



(6) Give an account of the structure of the epidermis of a leat. 



(7) What is a vascular bundle ? Of what parts does it consist ? (1898. ) 



(8) What is the cambium ? Explain where you would find it in the 

 trunk of a tree, and what its importance is? (1898.) 



(9) Describe the structure of a young parenchyma cell, and explain 

 how it differs from that of a full-grown cell of the same kind. (1892.) 



(10) Explain what is meant by ground tissue. In what parts of a 

 plant is ground tissue found ? 



(u) Give a short account of the longitudinal course of the vascular 

 bundle in a dicotyledonous plant. 



(12) What kinds of hairs are found on plants? Of what use to the 

 plant are hairs ? 



