· Permanent Tissue (Mature cells incapable of division)
§ Are tissues that have temporarily or permanently lost the power to divide
§ The cells formed by the apical meristem are differentiated into different types of permanent tissues
· Based on the constituent cells, the permanent tissue is classified into two types: –
§ Simple tissue
§ Tissues made up of cells with similar structure and function
§ Classified into;
· Parenchyma,
· Collenchyma and
· Sclerenchyma
§ Complex tissue
§ A tissue made up of several kinds of cells but all of them function together as a single unit
§ Classified into;
· Xylem tissue
o Xylem (Greek word ‘xylos’= wood)
o Xylem is made up of four kinds of cells
§ Tracheids
§ Vessels or tracheae,
§ Xylem fibres and
§ Xylem parenchyma
· Phloem tissues
o Phloem is composed of four types of cells:
§ Sieve elements,
§ Companion cells,
§ Phloem parenchyma and
§ Phloem fibres
· Companion cells are present only in angiosperms
References Evans, W. C. (2009). Trease and Evans Pharmacognosy. India: Reed Elsevier Limited