126 



PLANT ANATOMY. 



This is the classification that will be 

 here followed. 



(A) Formative tissues. Meristeni. 



(B) Protective tissues. 



1. Epidermal tissues. Epidermis, 



cork. 



2, Skeleton, or Mechanical, tissues. 



Bast fibres, Libriform, Scler- 

 otic, or Stone cells. 



(C) Tissues of Nutrition. 



1. Absorption, Root hairs, Haus- 



toria. 



2. Assimilation. Palisade cells and 



other leaf tissues. 



3. Respiration and Transpiration. 



Stomata, Lenticels. 



4. Conduction. Ducts and Sieve 



tubes. 



5. Secretion and Excretion. 



(D) Reproductive tissues. 



CHAPTER VK 



FORMATIVE TISSUES. 



Meristeniatic tissues are tissues that 

 liave the power of forming new cells, 

 hence the power of growth is said to be 

 ronfinod to them. In the higher plants 

 the points of merlstematic growth are to 



he found only at the apex of stems both 

 apical and lateral, the ends of roots, the 

 cambium layer, the phellogen layer and 

 I he tips of leaves and flower structures. 

 Under spt'cial circumstances other parts 

 may take on meristematic parts, as, for 



instance, when a plant is injured new 

 tissues, mainly of a corky character, 

 may be formed In large quantities. 



Meristematic cells are generally thin- 

 walled, square, angled, and filled with 

 protoplasm and provided with nuclei. In 

 some very rapidly growing meristems 

 the cell walls may be absent in the early 

 stages of growth, 



Meristematic tissue may be primary or 

 secondary. Primary meristem is found 



«• 



Fig. 26.— Apical ^owths. e. dermatogen, r. plerome, j>. periblem, 



